Method for forming resist patterns

ABSTRACT

Disclosed herein is a resist for forming patterns, which is greatly sensitive to ultraviolet rays an ionizing radiation, and which can therefore form a high-resolution resist pattern if exposed to ultra violet rays or an unionizing radiation. Hence, the resist is useful in a method of manufacturing semicon ductor devices having high integration densities. The resist comprises tert-butoxycarbonyl methoxypolyhydroxy styrene and an o-quinonediazide compound.

This is a division of application Ser. No. 07/876,457 filed on Apr. 30,1992, U.S. Pat. No. 5,403,695.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resist suitable for forming patternsduring the manufacture of semiconductor devices, particularly themanufacture of largescale integrated (LSI) circuits.

2. Description of the Related Art

Photolithography is used in some steps of manufacturing a semiconductordevice such as an LSI circuit. This technology is to etch substrate(e.g., a silicon single-crystal wafer), thereby to form fine lines andsmall widows. More specifically, a photoresist film is formed on thesubstrate by means of spin coating, and is then exposed to light appliedthrough a pattern mask. The film is developed and rinsed, and is therebymade into a resist pattern. Then, the substrate is etched by using theresist pattern, thereby forming fine lines and small widows in thesurface of the substrate.

It is increasingly desired that LSI circuits have higher integrationdensities. Here arises a demand for technology which can form lines andwindows in a substrate, which are finer and smaller than those made bythe existing photolithography. To meet this demand, use is made of alight source which can apply a light beam having as short a wavelengthas is possible to a photoresist film. More precisely, a deep UV source,such as an KrF excimer laser or an ArF excimer layer, is employed inphotolithography.

The conventional resist absorbs light having a short wavelength, so muchthat the sufficient light fails to reach that surface of the resist filmwhich faces away from the light-receiving surface. After the resist filmis developed and rinsed, it will have openings inevitably having a crosssection shaped like an inverted triangle. Consequently, when thesubstrate on which the resist film is formed is etched, using the resistfilm as etching mask, an original LSI is not transferred to thesubstrate, with sufficient accuracy.

To solve the problem with the conventional resist, it has been proposedthat so-called chemically amplified resist be utilized. A chemicallyamplified resist contains a compound which generates strong acid whenexposed to light (hereinafter referred to, when necessary, as "acidgenerator"), and also a compound in which hydrophobic groups aredecomposed by acid and which is thereby changed into a hydrophilicsubstance. Various resists of this type are known. To be more specific,U.S. Pat. No. 4,491,628 (1985) to H. Ito, C. G. Wilson, and J. M. J. Frechet discloses a positive resist containing a polymer wherein thehydroxyl group of poly(p-hydroxystyrene) is blocked by butoxycarbonylgroup, and onium salt which generates an acid when exposed to light.Also, M. J. O'Brien, J. V. Crivello, SPIE, Vol. 920, Advances in ResistTechnology and Processing, p. 42, (1988) discloses a positive resistcontaining m-creosol novolac resin, naphthalene-2-carboxylicacid-tert-butylester, and triphenylsulfonium salt. Further, H. Ito,SPIE, Vol. 920, Advances in Resist Technology and Processing, p. 33,(1988) discloses a positive resist containing onium salt and2,2-bis(4-tert-butoxycarbdnyloxyphenyl) propane or polyphthalaldehyde.

The acid generator acts as a catalyst, efficiently reacting with othersubstances. Hence, when light is applied to the resist film, chemicalreaction thoroughly takes place even in that surface of the film whichfaces away from the light-receiving surface and to which the light canhardly reach. As a result, the resist film can be made, after developedand rinsed, into a resist pattern having openings which has steep sides.

Each of the resists specified above contains onium salt used as acidgenerator. Onium salt includes arsenic or antimony which are harmful tohuman. In view of this, it would be questionable to put onium salt toindustrial use. In case arsenic or antimony remains on the substrate(e.g., a wafer) after the resist pattern has been removed, it willprobably impair the characteristics of the electronic circuit to beformed on the substrate. Resist containing onium salt has anotherdisadvantage. In the surface of a film of this resist, there willprobably be formed a layer which is hard to dissolve, inevitably makingscars in the upper surface of the resultant resist pattern. Such scarsare detrimental to the subsequent etching of the substrate.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a resist which ishighly sensitive to ultraviolet rays and ionizing radiation and has ahigh resolution, and which is therefore suitable for forming patternsduring the manufacture of semiconductor devices.

In a first aspect of the invention, there is provided a resist forforming patterns, which comprises:

(a) an acid-generating compound which generates an acid when exposed toa chemical radiation; and

(b) a compound which has an acid decomposable substituent group andwhich is represented by the following formula (I): ##STR1## where R¹ isa monovalent organic group, m is 0, 1, or a positive number greater than1, and n is a positive number.

In a second aspect of the invention, there is provided a resist forforming patterns, which comprises:

(a) a compound having an acid decomposable substituent group;

(b) an acid-generating compound which generates an acid when exposed toa chemical radiation; and

(c) carboxylic acid.

In a third aspect of the invention, there is provided a resist forforming patterns, which comprises:

(a) a compound having an acid decomposable substituent group;

(b1) a first acid-generating compound which generates a strong acid whenexposed to a chemical radiation; and

(b2) a second acid-generating compound which generates a acid weakerthan the strong acid, when exposed to a chemical radiation.

In a fourth aspect of the invention, there is provided a resist forforming patterns, which comprises:

(a) a compound having an acid decomposable substituent group; and

(b) o-quinonediazide compound.

The term "chemical radiation," used above, is a general name for energyradiation and matter radiation which chemically change a resist andencompasses X rays, ultraviolet rays having short wavelengths, andionizing radiation such as electron beams.

Resists (1) to (4) for forming patterns, all according to the invention,will be described in detail.

The resist (1) comprises an acid-generating compound, and a compoundwhich has an acid decomposable substituent group and which isrepresented by the following formula (I): ##STR2## where R¹ is amonovalent organic group, m is 0, 1, or a positive number greater than1, and n is a positive number.

R¹ can be any monovalent organic group. Nonetheless, its preferableexamples are: methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl,iso-butyl, sec-butyl, and benzyl. Of these groups, tert-butyl is themost preferable.

The value for n/(m+n) in the formula (I) ranges from 0.03 to 1,preferably 0.05 to 0.70. If n/(m+n) is less than 0.03, the difference inetching speed between a portion exposed to a chemical radiation and aportion not exposed thereto will be too small.

The compound represented by the formula (I), which will hereinafter bereferred to as "acid decomposable compound", is preferably one which hasa molecular weight of 1000 or more. If the acid decomposable compoundhas a molecular weight less than 1000, the resist will be lessheat-resistant than desired.

The acid generator, which generates acid when exposed to a chemicalradiation, can be various known compounds or various known mixtures.Examples of the acid generator are: salts such as diazonium salt,phosphonium salt, sulfonium salt and iodonium salt (e.g.,diphenyliodonium trifluoromethane sulfonate), organic halogen compounds,orthoquinone-diazidesulfonylchloride, and ester sulfonate. The organichalogen compounds are compounds which form hydrogen halogenide acid.These compounds are disclosed in U.S. Pat. Nos. 3,515,552, 3,536,489,and 3,779,778, and West German Offenlegungschrift 22 43 621. Othercompounds which generate acid when exposed to a chemical radiation aredisclosed in Published Unexamined Japanese Patent Applications 54-74728,55-24113, 55-77742, 60-3626, 60-138539, 56-17345, and 50-36209.

Specific examples of the compounds described above are:di(p-tert-butylphenyl) iodonium trifluoromethanesulfonate,diphenyliodonium trifluoromethanesulfonate, benzoine tosylate,o-nitrobenzyl p-toluenesul fonate, triphenylsulfoniumtrifluoromethanesulfonate, tri(tert-butylphenyl) sulfoniumtrifluoromethanesul fonate, benzendiazonium p-toluenesulfonate, 4-(din-propylamino)-benzonium tetrafluorobrate,4-p-tolyl-mercapto-2,5-diethoxy-benzendiazonium hexafluorophos phate,tetrafluoroborate, diphenylamine-4-diazonium sulfate,4-methyl-6-trichloromethyl-2-pyrone,4-(3,4,5-trimethoxy-styryl)-6-trichloromethyl-pyrone,4-(4-methoxy-styryl)-6-(3,3,3-trichloro-propenyl)-2-pyrone,2-trichloromethyl-benzimidazole, 2-tribromomethyl-quinoline,2,4-dimetyl-1-tribromoacetyl benzene, 4-dibromoacetyl-benzoic acid,1,4-bis-dibromomethyl-benzene, tris-dibromomethyl-S-triazine,2-(6-methoxy-naphtyl-2-yl)-4,5-bis-trichloromethyl-S-triazine,2-(naphtyl-1-yl)-4,6-bis-trichloromethyl-S-triazine,2-(naphtyl-2-yl)-4,6-bis-trichloromethyl-S-triazine,2-(4-ethoxyethyl-naphtyl-1-yl)-4,6-bis-trichloromethyl-S-triazine,2-(benzopyranyl-3-yl)-4,6-bis-trichloro-methyl-S-triazine,2-(4-methoxy-anthoracyl-1-yl)-4,6-bis-trichloromethyl-S-triazine,2-(phenantyl-9-yl)-4,6-bis-trichloromethyl-S-triazine,o-naphthoquinonediazide-4-sulfonic chloride, and the like.

Specific examples of ester sulfonate: naphtho-quinoneazide-4-estersulfonate, naphthoquinonediazide-5-ester sulfonate, p-toluenesulfonicacid-o-nitrobenzyl ester, p-toluenesulfonic acid-2,6-dinitrobenzylester, and the like.

It is desirable that the acid generator be o-quinonediazide compound. Apreferable example of o-quinonediazide compound is ester made fromo-quinonediazide sulfonic acid and phenol compound, which can beprepared by reacting o-quinonediazide sulfonic chlroide with phenolcompound by the ordinary method. The o-quinonediazide sulfonic chloridecan be 1-benzophenone-2-diazo-4-sulfonic chloride,1-naphthoquinone-2-diazo-5-sulfonic chloide,1-naphthoquinone-2-diazo-4-sulfonic chloride, or the like. Examples ofthe phehol compound are: phenol, cresol, xylenol, bisphenol A, bisphenolS, hydroxybenzophenone,3,3,3',3'-tetramethyl-1,1'-spiroindan-5,6,7,5',6',7'-hexanol,phenolphthalein, p-hydroxybenzylidene maleic dimethyl,p-hydroxybenzylidene maleic diethyl, cyanophenol, nitrophenol,nitrosophenole, hydroxyacetophenone, trihydroxy methyl benzoate,polyvinylphenol, novolac resin, and the like.

Such o-quinonediazide compounds as described above are shown in Tables 1to 5 attached hereto.

Of these o-quinonediazide compounds, 1-naphtho-quinone-2-diazo-4-estersulfonate is the most desirable. This ester generates carboxylic acidand sulfonic acid stronger than carboxylic acid when exposed to achemical radiation, as is described in J. J. Grunwald, C. Gal, S.Eidelman, SPIE, Vol. 1262, Advances in Resist Technology and ProcessingVII, p. 444, (1990). The ester performs a prominent catalytic action andis, therefore, useful.

The resist (1) according to the invention contains 0.1 to 30 wt %, morepreferably 0.5 to 20 wt %, of the components of the resist (1). If theamount of the acid generator used is less than 0.1 wt %, the resist canhardly be sufficiently sensitive to light. If the amount of the acidgenerator is more than 30 wt %, the resist (1) may fail to form ahomogeneous resist film, or residue may be formed after the resist filmhas been developed or etched.

The resist (1) can comprise carboxylic acid as a third component, inaddition to the acid decomposable compound and the acid generator. Thecarboxylic acid increases the speed at which the resist (1) is dissolvedin alkali aqueous solution, so that less scars than otherwise may beformed in the surface of the resist pattern to be formed of the resist(1). The carboxylic acid can be any one that can mix uniformly with theother components of the resist (1). Specific examples of the carboxylicacid are: formic acid, acetic acid, propionic acid, butyric acid,2-methylpropanoic acid, valeric acid, isovaleric acid, α-methylbutyricacid, trimethylacetic acid, hexanoic acid, 4-methylpentanoic acid,2-methylbutanoic acid, 2,2-dimethybutanoic acid, heptanoic acid,octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoicacid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid,octadecanoic acid, eicosanoic acid, docosanoic acid, hexacoanoic acid,triaconoic acid, oxalic acid, malonic acid, succinic acid, glutaricacid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacicacid, ascorbic acid, tridecanedioic acid, methylmaloic acid, dimethylmaloic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid,2,3-dimethylsuccinic acid, tetramethylsuccinic acid,1,2,3-propanetricarboxylic acid, 1,2,3-propanetricarboxylic acid,2,3-dimethylbutane-1,2,3-tricarboxylic acid, fluoroacetic acid,trifluoroacetic acid, chloroacetic acid, dichloroacetic acid,trichloroacetic acid, bromoacetic acid, iodoacetic acid,2-chloropropionic acid, 3-chloropropionic acid, 2-bromopropionic acid,3-bromopropionic acid, 2-iodopropionic acid, 2,3-dichloropropionic acid,chlorosuccinic acid, bromosuccinic acid, 2,3-dibromosuccinic acid,hydoxyacetic acid, lactic acid, 2-hydroxybutyric acid,2-hydroxy-2-methylpropanoic acid, 2-hydroxy-4-methypentanoic acid,3-hydroxy-3-pentanecarboxylic acid, 3-hydroxypropionic acid,10-hydroxyoctanedecanoic acid, 3,3,3-trichloro-2-hydroxypropionic acid,2-(lactoyloxy) propionic acid, glyceric acid, 8,9-dihydroxyoctadecanoicacid, tartronic acid, malic acid, acetoxysuccinic acid,2-hydroxy-2-methylbutanedioic acid, 3-hydroxypentanedioic acid, tartaricacid, d-ethylhydrogentartrate, tetrahydroxysuccinic acid, citric acid,1,2-dihydorxy-1,1,2-ethane-tricarboxylic acid, ethoxyacetic acid,2,2'-oxydiacetic acid, 2,3-epoxypropionic acid, pyruvic acid,2-oxysobutyric acid, acetoacetic acid, 4-oxovaleric acid,9,10-dioxyoctadecanoic acid, mesoxalic acid, oxyaloacetic acid,3-oxoglutaric acid, 4-oxoheptainedioic acid, benozic acid, toluic acid,ethylbenzoic acid, p-isopropylbenzoic acid, 2,3-dimethylbezonic acid,2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 3,5-dimethylbenzoicacid, 2,4,5-trimethylbenzoic acid, phthalic acid, isophthalic acid,terephthalic acid, 5-methylisophthalic acid, 1,2,3-benzenetricarboxylicacid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid,1,2,3,4-benzenetetracarboxylic acid, 1,2,3,5-benzenetetracarboxylicacid, 1,2,4,5-benzenetetracarboxylic acid, benzenepentacarboxylic acid,benzenhexacaroxylic acid, fluorobenzoic acid, chlorobenzoic acid,dichlorobenzoic acid, trichlorobenzoic acid, bromobenzoic acid,dibromobenzoic acid, iodobenzoic acid, chlorophthalic acid,dichlorophthalic acid, tetrachlorophthalic acid, nitrosobenzoic acid,o-nitrobezonic acid, p-nitrobenzoic acid, 2,4-dinitrobenzoic acid,2,4,6-nitrobenzoic acid, 3-nitrobenzoic acid, 5-nitroisophthalic acid,2-nitroterephthalic acid, p-hydroxybenzoic acid, salicylic acid,5-chlorosalicylic acid, 3,5-dichlorosalicylic acid, 3-nitrosalicylicacid, 3,5-dinitrosalicylic acid, 2,4-dihyroxybezonic acid,3,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid,3,4-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid,2,3,4-trihydroxybenzoic acid, 6-hydroxy-2-toluic acid,2-hydroxy-3-toluic acid, 5-hydroxy-3-toluic acid, 2-hydroxy-4-toluicacid, 2-hydroxy-3-isopropyl-6-methylbenzoic acid,4-hydroxy-5-isopropyl-2-methylbenzoic acid, 2,4-dihyroxy-6-methylbenzoicacid, 2-hydroxyphthalic acid, 4-hydroxyisophthalic acid,2-hydoxyterephthalic acid, 3,4-dihydroxyphthalic acid,2,5-dihydroxyphthalic acid, 2-hydroxy-1,3,5-benzenetricaboxylic acid,(hydroxymethyl) benzoic acid, (1-hydroxy-1-methylethyl) benzoic acid,anisic acid, vanillic acid, 3-hydroxy-4-methoxybenzoic acid,3,4-dimethoxybenzoic acid, 3,4-methylenedioxybenzoic acid,3,4,5-trimethoxybenzoic acid, 3,4-dimthoxyphthalic acid,o-phenoxybenzoic acid, o-acetoxybenzoic acid, 3-o-galloylgallic acid,p-acetylbenzoic acid, p-benzoylbenzoic acid, 4,4'-carbonyldibenzoicacid, p-acetoamidebenzoic acid, o-benzoamidebenzoic acid, phthalanilicacid, phenylacetic acid, 2-phenylpropionic acid, 3-phenylpropionic acid,4-phenylbutyric acid, p-hydroxyphenylacetic acid,2,5-dihydroxyphenylacetic acid, 3-(o-hydroxyphenyl) propionic acid,2,3-dibromo phenylpropionic acid, α-hydroxyphenylacetic acid,2-hydroxy-2-phenylpropionic acid, 2-hydroxy-3-phenyl propionic acid,3-hydroxy-2-phenylpropionic acid, 3-hydroxy-3-phenylpropionic acid,2,3-epoxy-3-phenyl propionic acid, phenylsuccinic acid, o-carboxyphenylacetic acid, 1,2-benzenediacetic acid, phenylglyoxylic acid,o-carboxyglyoxylic acid, phenylpyruvic acid, benzoylacetic acid,3-benzoylpropionic acid, phenoxyacetic acid, benzoyloxyacetic acid,2-benzoyloxypropionic acid, succinanilic acid, carbanylic acid, oxanilicacid, o-carboxyoxanilic acid, 4-biphenylcarboxylic acid,2,2'-biphenyldicarboxylic acid, benzylbenzoic acid, diphenylacetic acid,α-hydroxydiphenylacetic acid, o-benzhydrylbenzoic acid, phenolphthalin,triphenylacetic acid, uvic acid, 5-methyl-2-furancarboxylic acid,2-furancarboxylic acid, furilic acid, paraconic acid, terebic acid,terpenylic acid, aconic acid, coumalic acid, comanic acid, comenic acid,chelidonic acid, meconic acid, and the like.

The resist (1) according to the invention contains 0.5 to 20 wt %, morepreferably 1 to 10 wt %, of the carboxylic acid, based on the totalweight of the solid components of the resist (1). If the amount of thecarboxylic acid used is less than 0.5 wt %, the resist can hardly bemade into a resist film having a good pattern after exposed to achemical radiation and subjected to development. On the other hand, ifthe amount of the carboxylic acid is more than 20 wt %, the differencein etching speed between a portion exposed to a chemical radiation and aportion not exposed thereto will be too small.

The resist (1) can comprise alkali-soluble polymer as a fourthcomponent, in addition to the acid decomposable compound and the acidgenerator, and the carboxylic acid.

It is desirable that the alkali-soluble polymer is a resin containingaryl group or carboxy group, with hydroxy group introduced into it.Specific examples of the resin are: phenol novolac resin, cresol novolacresin, xylenol novolac resin, vinyphenol resin, isopropenylphenol resin,a copolymer of vinylphenol and at least one compound selected from thegroup consisting of acrylic acid, methacrylic acid derivative,acrylonitrile, styrene devivative or the like, a copolymer ofisopropenylphenol and at least one compound slected from the groupconsisting of acrylic acid, methacrylic acid derivative, acrylonitrile,and styrene derivative, a copolymer of styrene derivative and at leastone compound selected from the group consisting of acrylic resin,methacrylic resin, acrylic acid, methacrylic acid, maleic acid, maleicanhydride, and acrylnitrile, and silicon-containing compounds of any ofthe polymers specified here.

Of the polymers mentioned above, resins containing aromatic rings arepreferred since they render the resist (1) sufficiently resistant to dryetching. For example, phenol novolac resin and creasol novolc resin arepreferable. Specific examples of the alkali-soluble polymers arespecified in Tables 6, 7 and 8 attached hereto. Also, a phenol resin canbe used which has its transparency improved by being oxidized, thuscontaining quinone, and then by reducing the quinone thus formed.

It is desirable that the amount of the alkali-soluble polymer used be 90parts by weight or less, preferably 80 parts by weight or less, wherethe total amount of the acid-decomposable compound and thealkali-soluble polymer is 100 parts by weight. If the polymer is used inan amount greater than 90 parts by weight, the difference in etchingspeed between a portion exposed to a chemical radiation and a portionnot exposed thereto will be excessively small, inevitably decreasing theresolution of the resist (1).

The resist (1) can comprise, if necessary, a sensitizer, a dye, asurfactant, and a dissolution inhibitor, in addition to the aciddecomposable compound, the acid generator, the carboxylic acid, and thealkali-soluble polymer.

The resist (1) is prepared by dissolving the acid decomposable compound,the acid generator, the carboxylic acid and the alkali-soluble polymerin an organic solvent, and by filtering the resultant solution. Examplesof the organic solvent are: ketone-based solvents such as cyclohexanone,acetone, methyl ethyl ketone, and methyl isobutyl ketone;cellosolve-based solvents such as methyl cellosolve, methyl cellosolveacetate, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve,and butyl cellosolve acetate; and ester-based solvents such as ethylacetate, butyl acetate, isoamyl acetate, ethyl lactate, and methyllactate. Other examples of the organic solvent are:N-methyl-2-pyrrolidone, dimethylformamide, dimethylactoamide,dimethylsulfoxide, and the like. The solvents, exemplified here, can beused singly or in combination. Each can contain an appropriate amount ofxylene, toluene or aliphatic alcohol (e.g., isopropyl alcohol).

The resist (2) for forming patterns, according to the invention,comprises a compound having an acid decomposable substituent group(hereinafter called "acid decomposable compound"); a compound whichgenerates acid when exposed to a chemical radiation (hereinafterreferred to as "acid generator"); and carboxylic acid.

The acid decomposable compound can be any compound that is decomposed byacid to have its solubility to developing liquid changed. Specificexamples of this compound are: phenol, cresol, xylenol, bisphenol A,bisphenol S, hydroxybenzophenone,3,3,3',3'-tetramethyl-1,1'-spiroindan-5,6,7,5'6',7'-hexanol,phenolphthalein, polyvinylphenol, novolac resin, and the like. Thehydroxyl group in these acid decomposable compound is esterified with aproper estrifying agent, or etherified with an appropriate etherifyingagent. Examples of the ester or ether to be introduced into the compoundare: methyl ester, ethyl ester, n-propyl ester, iso-propyl ester,tert-butyl ester, n-butyl ester, isobutyl ester, benzyl ester,tetrahydro pyranyl ether, benzyl ether, methyl ether, ethyl ether,n-propyl ether, iso-propyl ether, tert-butyl ether, aryl ether,methoxmethyl ether, p-bromophenacyl ether, trimethylsilyl ether,benzyloxycarbonyl ether, tert-butoxycarbonyl ether, tert-butylacetate,4-tert-butylbenzil ether, and the like. It is desirable that the aciddecomposable compound be one represented by the general formula (I)described above in connection with the resist (1).

The acid generator contained in resist (2) is similar to that used inthe resist (1). The acid generator, which is used along with thecarboxylic acid, can be one of various known compounds or a mixturethereof. Nonetheless, o-quinonediazide compound, also used in the resist(1), is preferred. In particular, 1-naphthoquinone-2-diazo-4-estersulfonate is the most preferable. The acid generator should be used inan amount of 0.1 to 30 wt %, more preferably 0.5 to 20 wt %, based onthe total weight of the solid components of the resist (2), for the samereason as a similar acid generator is used in the resist (1).

The carboxylic acid contained in the resist (2) is similar to the thirdcomponent of the resist (1). It is desirable that the carboxylic acid beused in an amount of 0.5 to 20 wt %, more preferably 1 to 10 wt %, basedon the total weight of the solid components of the resist (2), for thesame reason as carboxylic acid is used in the resist (1).

The resist (2) can comprise an alkali-soluble polymer similar to thatone used in the resist (1), in addition to the acid decomposablecompound, the acid generator, and the carboxylic acid. The polymershould be used in an amount of 90 parts by weight or less, preferably 80parts by weight or less, where the total amount of the acid-decomposablecompound and the alkali-soluble polymer is 100 pats by weight, as in thecase of the resist (1). If neither the acid-decomposable compound northe acid generator is a polymer, it would be desirable that thealkali-soluble polymer, described above, be used as a fourth componentof the resist (2).

The resist (2) can comprise, if necessary, a sensitizer, a dye, asurfactant, and a dissolution inhibitor, in addition to the aciddecomposable compound, the acid generator, and the carboxylic acid.

The resist (2) is prepared by dissolving the acid decomposable compound,the acid generator, the carboxylic acid, and, if necessary, thealkali-soluble polymer and other components, in such an organic solventas is used to prepare the resist (1), and by filtering the resultantsolution.

The resist (3) for forming patterns, according to the invention,comprises: compound having an acid decomposable substituent group(hereinafter re ferred to as decomposable substituent group (hereinafterre ferred to as "acid-decomposable compound"); a compound whichgenerates strong acid when exposed to a chemical radiation (hereinaftercalled "first acid generator"); and a compound which generates acidweaker than the strong acid, when exposed to a chemical radiation(hereinafter referred to as "second acid generator").

The acid-decomposable compound used in the resist (3) can be selectedfrom those specified above as examples of the acid-decomposable compoundused in the resist (2). Preferably, it is one represented by the formula(I).

The first acid generator is a compound which generates a strong acidhaving pK value of less than 3 (K is electrolytic dissociationconstant), when it is exposed to a chemical radiation. The first acidgenerator can be a compound similar to the acid generator used in theresist (1). Preferable examples are the o-quinonediazide compoundsspecified in connection with the resist (1). Of these o-quinonediazidecompounds, 1-naphthoquinoue-2-diazo-4-ester sulfonate is the mostdesirable.

The first acid generator is used in the resist (3), in an amount of,preferably, 0.1 to 20 wt %, more preferably 0.5 to 10 wt %. If it isused in an amount less than 0.1 wt %, the resist (3) will hardly have asufficient light-sensitivity. If it is used in an amount of more than 20wt %, the resist (3) will fail to form an uniform resist film, or theresidue of this resist will likely be formed after the film of theresist is developed or etched.

The second acid generator is a compound which generates a weak acidhaving pK value of 3 or more (K is electrolytic dissociation constant),when it is exposed to a chemical radiation. Examples of this acidgenerator are: 1,2-naphthoquinonediazide-5-ester sulfonate, 5-diazomeldram's acid, a derivative of 5-diazo meldrum's acid, and a derivativeof diazodimedone.

The second acid generator is used in an amount of 1 to 30 wt %, morepreferably 5 to 20 wt %, based on the total weight of the solidcomponents of the resist (3). If the second acid generator is used in anamount of less than 1 wt %, it will be difficult to prevent forming of ahardly soluble layer on the resultant resist film. On the other hand, ifthe second acid generator is used in an amount of more than 30 wt %, itwill be difficult to form a uniform resist film, or there will be therisk that resist residue will be formed after the resist film of theresist is developed or etched.

The resist (3) can comprise a carboxylic acid similar to that one usedin the resist (1) and an alkali-soluble polymer, used as fourth andfifth components, respectively, in addition to the acid-decomposablecompound, the first acid generator and the second acid generator. Thecarboxylic acid should better be used in an amount of 0.5 to 20 wt %,more preferably 1 to 10 wt %, based on the total weight of the solidcomponents of the resist (2), for the same reason as carboxylic acid isused in the resist (1). The alkali-soluble polymer should be used in anamount of 90 parts by weight or less, preferably 80 parts by weight orless, where the total amount of the acid-decomposable compound and thealkali-soluble polymer is 100 pats by weight, as in the case of theresist (1). If none of the acid-decomposable compound, the first acidgenerator and the second acid generator is a polymer, it would bedesirable that the alkali-soluble polymer, described above, be used as afifth component of the resist (3).

The resist (3) can comprise, if necessary, a sensitizer, a dye, asurfactant, and a dissolution inhibitor, in addition to the aciddecomposable compound, the acid generator, and the carboxylic acid.

The resist (3) is prepared by dissolving the acid decomposable compound,the first acid generator and the second acid generator, and, ifnecessary, the carboxylic acid, the alkali-soluble polymer, and othercomponents, in such an organic solvent as is used to prepare the resist(1), and by filtering the resultant solution.

The resist (4) for forming patterns, according to the present invention,comprises: a compound having an acid decomposable substituent group; ando-quinonediazide compound.

The acid-decomposable compound used in the resist (4) can be selectedfrom those specified above as examples of the acid-decomposable compoundused in the resist (2). Preferably, it is one represented by the formula(I).

The second component of the resist (4), i.e., o-quinonediazide compound,is similar to the acid generator used in the resist (1). A preferableexample of o-quinonediazide compound is 1-naphthoquinone-2-diazo-4-estersulfonate.

It is desirable that the second component be used in an amount of 0.1 to30 wt %, preferably 0.5 to 20 wt %, based on the total weight of thesolid components of the resist (2), for the same reason as the acidgenerator is used in the resist (1).

The resist (4) can comprise carboxylic acid similar to that carboxylicacid used in the resist (1) and an alkali-soluble polymer, as third andfourth components, respectively, in addition to the acid-decomposablecompound and o-quinonediazide compound. The carboxylic acid shouldbetter be used in an amount of 0.5 to 20 wt %, more preferably 1 to 10wt %, based on the total weight of the solid components of the resist(2), for the same reason as carboxylic acid is used in the resist (1).The alkali-soluble polymer should be used in an amount of 90 parts byweight or less, preferably 80 parts by weight or less, where the totalamount of the acid-decomposable compound and the alkali-soluble polymeris 100 pats by weight, as in the case of the resist (1). If neither theacid-decomposable compound nor o-quinonediazide compound is a polymer,it would be desirable that the alkali-soluble polymer, described above,be used as a forth component of the resist (4).

The resist (4) can comprise, if necessary, a sensitizer, a dye, asurfactant, and a dissolution inhibitor, in addition to the aciddecomposable compound, the acid generator, and the carboxylic acid.

The resist (4) is prepared by dissolving the acid decomposable compoundand o-quinonediazide compound, and, if necessary, the carboxylic acid,the alkali-soluble polymer, and other components, in such an organicsolvent as is used to prepare the resist (1), and by filtering theresultant solution.

A method of forming a pattern on a substrate, by using any one of theresists (1) to (4) according to the present invention, will now bedescribed.

First, the resist is coated on a substrate by means of spin-coating ordipping. The resist, thus coated, is dried at 150° C. or less,preferably 70° to 120° C., thereby forming a film of the resist. Thesubstrate is a silicon wafer, a silicon wafer having insulating layers,electrodes and wires formed on its surface, and thus having steppedportions, a blank mask, or a III-V compound semiconductor wafer (e.g., aGaAs wafer or an AlGaAs wafer).

Next, ultraviolet rays (preferably, deep-Uv) or an ionizing radiation isapplied onto the resist film through a mask which has a desired pattern.In the case of the film made of the resist (1), for example, the acidgenerator generates an acid. The acid reacts with the acid-decomposablecompound. Examples of the ultraviolet rays are: the beams emitted by aKrF, ArF, XeF or XeCl excimer laser and the i-line, h-line or g-lineemitted by a mercury lamp. Examples of the ionizing radiation are:electron beams and X-rays. In the exposure process described above, theresist film can be scanned with an electron beam, not irradiated withultraviolet rays or the ionizing radiation. If this is the case, nomasks are unnecessary, and the electron beam is applied directly ontothe resist film.

Thereafter, the resist film is heated to 70° to 160° C., preferably 80°to 150° C. During the heating, the reaction between theacid-decomposable compound and the acid generated by the acid generatoris accelerated. The resist film is heated to a temperature within therange specified above, for the following reasons.

If the resist film is heated to a temperature lower than 70° C., theacid generated by the acid generator will fail to sufficiently reactwith the acid-decomposable compound. On the other hand, if the resistfilm is heated to a temperature higher than 160° C., both the exposedportions of the film and the unexposed portions thereof will bedecomposed or hardened.

Then, the resist film, thus heated, is developed with an alkali aqueoussolution, whereby a desired resist pattern is formed. Examples of thealkali aqueous solution are: inorganic alkali aqueous solutions such asaqueous solution of potassium hydroxide, aqueous solution of sodiumhydroxide, aqueous solution of sodium carbonate, and aqueous solution ofsodium silicate, sodium metasilicate; organic alkali aqueous solutionssuch as aqueous solution of tetramethylammonium hydroxide and aqueoussolution of trimethylhydroxyethyl ammonium hydroxide; and a mixture ofany of these compounds and alcohol, suractant or the like.

The resist pattern, thus formed, is washed with water, whereby thedeveloping solution is removed. The resist pattern is finally dried,along with the substrate on which it is formed.

In the method of forming a resist pattern, described above, step bakingcan be carried out, in which the substrate is gradually heated after thedevelopment of the resist film, thereby bridging the resin component ofthe resist film. Alternatively, deep-UV curing can be performed, inwhich deep ultraviolet rays are applied to the resist film, whileheating the film, thereby bridging the resin component of the resistfilm. Either process serves to improve the heat resistance of theresultant resist pattern.

According to the invention, the resist film can be immersed in alow-concentration alkali aqueous solution, either before or after it isexposed to a chemical radiation, and then can be subjected todeveloping. Once the resist film is treated with the low-concentrationalkali aqueous solution, its unexposed portions will be dissolved atlower speeds, which increases the contrast of the resultant reliefimage. The alkali aqueous solution can be replaced by amine such astrimethylamine, triethanolamine or hexamethylsilazane. Instead of beingimmersed in amine, the resist film can be exposed to vapor of the amine.Moreover, the resist film can be exposed to an alkali aqueous solutionand then, if necessary, be heat-treated.

Further, according to the invention, fog exposure can be conducted onthe resist film, in which the entire surface of the resist film alreadypattern-exposed is exposed to light, while the film is being heated. Thefog exposure decreases the speed with which the unexposed portions ofthe resist film are dissolved, thereby enhancing the resolution of theresist film.

Moreover, in the method of forming a resist pattern, a layer of acidicwater-soluble polymer can be formed on the resist film prior to theexposure thereof, in the case where the film is made of either theresist (1) or the resist (4). More specifically, this layer is formed,by preparing an aqueous solution of the polymer by dissolving thepolymer with pure water, then coating the aqueous solution on the resistfilm by means of spin coating or deposition, and finally drying thecoated solution at 150° C. or less, preferably 120° C. or less. Thelayer, thus formed on the resist film, prevents a hardly soluble layerfrom being formed on the resist film.

Preferably, the acidic water-soluble polymer is one having carboxy groupor sulfo group as a substituent group. Specific examples of the acidicwater-soluble polymer are: polyacrylic acid, polymethacrylic acid,polystyrenesulfonic acid, polymalic acid, polyitaconic acid,ethylene-anhydrous maleic acid copolymer, ethylene-methacrylic acidcopolymer, ethylvinylether-anhydrous maleic acid copolymer, andstyrene-anhydrous maleic acid copolymer. These acidic water-solublepolymers can be used singly or in combination. When any of thesepolymers, that contains anhydrous maleic acid, is dissolved in purewater, the anhydrous bond is cleaved, forming carboxylic acid. As aresult of this, the polymer will exhibit acidity.

The layer of acidic water-soluble polymer can contain a surfactant whichserves as coating modifier.

It is desirable that the polymer layer have a thickness of 10 to 1,000nm, more preferably 50 to 500 nm. If the layer is less than 10 nm thick,it may fail to prevent a hardly soluble layer from being formed on theresist film. If the layer is more than 1,000 nm thick, it may reduce theresolution of the resist film. The thickness of the polymer layer doesnot depend on the thickness of the resist film. Rather, it depends onthe thickness of a hardly soluble layer that might be formed if thepolymer layer were not formed.

The resist film having the polymer layer formed on it is exposed to achemical radiation applied through a mask, then heated to apredetermined temperature, and finally developed with an alkali aqueoussolution. During the developing process, the polymer layer is removedfrom the entire surface of the resist film, from both the exposedportions and the unexposed portions. Thereafter, either the exposedportions of the resist film or the unexposed portions thereof areremoved from the substrate, whereby a resist pattern is formed.Alternatively, the polymer layer can be washed away with pure waterprior to the development process, so that the resist film may thereafterbe developed. In this case, it is possible to prevent the alkaliconcentration of the alkali aqueous solution (i.e., the developingsolution) from being changed by the acidic water-soluble copolymer whichform the layer on the resist film. This serves to form a resist patternof high resolution.

In the resist (1) according to the invention, the acid generatorperforms two functions. It functions as a dissolution inhibitor in eachunexposed portion of the resist film, and also generates acid in eachexposed portion of the resist film. The acid-decomposable compoundrepresented by the formula (I) is decomposed by the acid generated bythe acid generator, generating carboxylic acid. Thus, this compound ismore easily dissolved in the developing solution than otherwise. Hence,the compound of the formula (I) can be dissolved at a speed much higherthan the compounds which have been hitherto used and which generatesphenol when decomposed by acid. This follows that the exposed portionsof the film made of resist (1) are dissolved much faster than theunexposed portions. Therefore, the resist (1) is highly sensitive andcan be processed into a high-resolution resist pattern. Even if the acidgenerator is one which generates weak acid when exposed to a chemicalradiation, the exposed portions of the resist film are dissolved fasterstill than the unexposed portions. In other words, a variety of acidgenerators can be used in this invention.

If the acid generator is o-quinonediazide compound, it will moreeffectively suppress the erosion of the substrate than does onium slatwhich is contained in the conventional resists. The use ofo-quinonediazide compound is also advantageous in that it is lessharmful than onium salt, rendering the resist (1) easy to handle.Moreover, unlike films of the conventional chemically amplified resists,a film of the resist (1) hardly has scars on its surface. Therefore,after a film of the resist (1) is developed and rinsed, it will haveopenings having a rectangular cross section, thus providing a fineresist pattern.

In the case the resist (1) contains carboxylic acid as the thirdcomponent, it can be more readily dissolved in an alkali developingsolution, thereby reducing the possibility that a hardly soluble layeris formed on the resist film as is inevitable with the chemicallyamplified resists. Also does this help the resist (1) to form a fineresist pattern which has openings each having a rectangular crosssection.

Further, if the resist (1) contains an alkali-soluble resin as thefourth component, it is possible to control the solubility of theexposed portions of the film of the resist (1). Hence, the resist (1)according to the invention is highly light-sensitive and can, therefore,have high resolution.

In the resist (2) according to the invention, the acid generator playstwo roles. It functions as a dissolution inhibitor in each unexposedportion of the resist film, and also generates acid in each exposedportion of the resist film. The acid, thus generated, reacts with theacid-decomposable compound, decomposing this compound. As a result, theexposed portion of the resist film are dissolved and removed, morereadily than the unexposed portion, as the resist film is developed andrinsed. The resist (2) has high light-sensitivity and can, therefore,provide a fine resist pattern.

By virtue of its third component of the resist (2), i.e., carboxylicacid, the resist (2) is very soluble to an alkali developing solution.Thus, unlike films of chemically amplified resists, a film made of theresist (2) will hardly have a layer in its upper region, which has scarsand is hard to dissolve. Obviously, the resist (2) serves to form a fineresist pattern which has openings each having a rectangular crosssection.

If an alkali-soluble resin is used as the fourth component in the resist(2), it is possible to control the solubility this resist exhibits tothe alkali developing solution. The resist (2) can, therefore, have animproved light-sensitivity and an enhanced resolution.

In the resist (3) according to the invention, the first acid generator,which generates a strong acid when exposed to a chemical radiation,plays two roles. It functions as a dissolution inhibitor in eachunexposed portion of the resist film, and also generates strong acid ineach exposed portion of the resist film. The strong acid, thusgenerated, reacts with the acid-decomposable compound, decomposing thiscompound. As a result, the exposed portion of the resist film aredissolved and removed more readily than the unexposed portion, as theresist film is developed and rinsed. The resist (3) has highlight-sensitivity and can, therefore, provide a fine resist pattern.

The second acid generator contained in the resist (3), which generatesweak acid when exposed to a chemical radiation, serves to decompose theacid-decomposable compound, either little or not at all. Nonetheless, itmakes the resist (3) more easy to dissolve in the alkali developingsolution, thereby increasing the solubility of the resist (3). In otherwords, the second acid generator helps to reduce the possibility that ahardly soluble layer is formed on the resist film as is inevitable withthe chemically amplified resists. This enables the resist (3) to form afine resist pattern which has openings each having a rectangular crosssection.

In the resist (4) according to this invention, o-quinonediazide compoundused as the second component, also performs two functions. It functionsas a dissolution inhibitor in each unexposed portion of the resist film,and also generates acid in each exposed portion of the resist film. Theacid, thus generated, reacts with the acid-decomposable compound,decomposing this compound. As a result, the exposed portion of theresist film are dissolved and removed more readily than the unexposedportion, as the resist film is developed and rinsed. The resist (4) hashigh light-sensitivity and can, therefore, provide a fine resistpattern. The second component of the resist (4), i.e., o-quinonediazidecompound, suppresses the erosion of the substrate, more effectively thandoes onium slat which is contained in the conventional resists. The useof o-quinonediazide compound is also advantageous in that it is lessharmful than onium salt, making the resist (4) easy to handle. Moreover,by virtue of o-quinonediazide compound, a film of the resist (4) hardlyhas scars on its surface, unlike films of the conventional chemicallyamplified resists. Therefore, after a film of the resist (4) isdeveloped and rinsed, it will have openings having a rectangular crosssection, thus providing a fine resist pattern.

Further, carboxylic acid, if used as the third component in the resist(4), renders the resist very soluble in an alkali developing solution.Thus, unlike films of chemically amplified resists, a film made of theresist (4) will hardly have a layer in its upper region, which has scarsand is hard to dissolve. Hence, the resist (4) serves to form a fineresist pattern which has openings each having a rectangular crosssection. If an alkali-soluble resin is used as the fourth component inthe resist (4), it is possible to control the solubility the exposedportions of the resist film exhibit to the alkali developing solution.Thus, the alkali-soluble resin enables the resist (4) to have itslight-sensitivity improved and its resolution enhanced.

The films of the resists (1) to (4) according to the invention can besubjected to the processes which have been hitherto conducted onpositive-type resists containing naphthoquinone diazide, such as alkalitreatment for improving the image contrast of a resist pattern to beformed, step baking or deep-Uv curing for enhancing the heat-resistanceof a resist pattern to be formed. By performing these processes, otherprocesses such as exposure and development can be effected under morearbitrary conditions than otherwise.

In the method of forming a resist pattern of the resist (1), (2), (3) or(4), the resist is coated on a substrate, thereby forming a resist film.The resist film is subjected to pattern exposure, whereby selectedportions of the resist film are exposed to a chemical radiation. In theexposed portions of the resist film, the acid generator generates anacid as it is exposed to the chemical radiation. The acid, thusgenerated, reacts with the acid-decomposable compound in the exposedportions of the film, thereby decomposing the acid-decomposablecompound. After the pattern exposure, the resist film is heated to apredetermined temperature, whereby the reaction of the acid with theacid-decomposable compound proceeds thoroughly from the exposed surfaceof the film to the unexposed surface thereof. As result, during thedeveloping process which follows the heating process, each exposedportion of the resist film is dissolved and removed in its entirety,more readily than the unexposed portions. As a result, the resist filmform a fine resist pattern which has openings having a rectangular crosssection.

Particularly, in the case of a film made of the resist (2), thecarboxylic acid increases the speed at which the resist (2) is dissolvedwith the alkali developing solution. In the case of a film made of theresist (3), the weak acid which the second acid generator generates whenexposed to a chemical radiation increases the solubility the resist (3)exhibits to an alkali developing solution. In other words, the secondacid generator helps to reduce the possibility that a hardly solublelayer is formed on the resist film as is inevitable with the chemicallyamplified resists. Therefore, the resist (3) can be processed, forming afine resist pattern which serves to manufacture a semiconductor devicehaving a high integration density.

In the method of forming a resist pattern of the resist (1) or (4), theresist is coated on a substrate, thus forming a resist film. A layer ofacid-soluble polymer is formed on the resist film. Next, the resist filmis pattern-exposed and heated to a predetermined temperature. In theexposed portions of the resist film, the acid generator generates acid.The acid reacts with the acid-decomposable compound. The reactionproceeds from the exposed surface of the resist film to the unexposedsurface thereof. During this reaction, the acid-soluble polymer layerprevents undesired substances in the process atmosphere from contactingthe resist film, whereby no hardly soluble layers, which are detrimentalto chemically amplified resist films, will be formed on the resist film.Even if a hardly soluble layer is formed on the acid-soluble polymerlayer, it will be dissolved along with the acid-soluble polymer layerwhen the resist film is developed after it has been pattern-exposed andheated. As a result, there will be formed a fine resist pattern whichhas openings having a rectangular cross section.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing, which is incorporated in and constitutes apart of the specification, illustrates presently preferred embodimentsof the invention and, together with the general description given aboveand the detailed description of the preferred embodiments given below,serves to explain the principles of the invention.

FIG. 1 is a cross-sectional view showing a pattern formed on a siliconwafer by means of Example 25 of the present invention; and

FIG. 2 is a cross-sectional view showing a pattern formed on a siliconwafer by means of a comparative example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Examples of the present invention will now be described in detail.

(Synthesis of Acid-Decomposable Compound)

First, 50 g of polyvinyl phenol (PHM-C manufactured by MaruzenPetrochemical) is dissolved with 200 ml of acetone in a 4-port flaskfilled with nitrogen gas, thereby preparing a solution. Next, 17.63 g ofpotassium carbonate, 8.48 g of potassium iodide, and 24.38 g oftert-butyl bromoacetate were added to the solution. The solution wasthen refluxed for 7 hours while being stirred. Thereafter, the insolublematter was filtered out, and acetone was distilled out. The resultantsubstance was dissolved in 150 ml of ethanol, thus forming a solution.This solution was dropped into 1.5 l of water, thereby depositing thepolymer. The polymer is filtered out and washed with water three times,every time with 300 ml of water. The polymer was then dried with windfor 12 hours. The polymer thus dried was dissolved in 200 ml of ethanol,precipitated, and refined. Further, the polymer was dried for 24 hoursby means of a vacuum drier at 50° C., whereby 2.0 g of polymer wasobtained. The results of ¹ H-NMR spectrum test showed that this polymerwas tert-butoxycarbonyl methoxypolyhydroxy styrene in which 35% of thehydroxy group in polyvinyl phenol had changed into tert-butoxycarbonylmethyl ether. The polymer, thus obtained, is an acid 2-decomposablecompound and will hereinafter be referred to as "Ba-35."

Six other polymers were prepared in the synthesized by the same methodas the compound Ba-35. These polymers differ from each other and fromthe compound Ba-35 in terms of substitution ratio of hydroxy group, asis shown in Table 9 (later presented).

(Components of Resist)

Acid-decomposable compounds other than those shown in Table 9 are shownin Tables 10 to 15 (later presented). Compounds which generate strongacid when exposed to a chemical radiation are shown in Tables 16 and 17(later presented). Compounds which generate weak acid when exposed to achemical radiation are shown in Table 19 (later presented).

(Resist-Preparing Method 1)

2.0 g of the acid-decomposable compound Ba-35 shown in Table 9, 0.44 gof o-quinonediazide compound QD-4 shown in Table 1 (later presented), inwhich number of Xs is 3 per molecule, and 2.0 g of polyvinyl phenol weredissolved in 13.8 g of ethyl cellosolve acetate, thus forming asolution. The solution was filtered by a filter having a mesh size of0.2 μm, thereby preparing resist RE-1.

(Resist-Preparing Methods 2 to 10)

The acid-decomposable compounds shown in Table 9, the o-quinonediazidecompounds shown in Tables 3 to 5, and polyvinyl phenol were mixed in theratios specified in Tables 20 and 21 (later presented), thus formingvarious mixtures. The mixtures were dissolved in the solvents shown inTables 20 and 21 and used in the amounts specified in Tables 20 and 21,too, thereby preparing 9 different solutions. These solutions werefiltered by a filter having a mesh size of 0.2 μm, thus preparing 9resists RE-2 to RE-10. Also shown in Table 20 is the composition of theresist RE-1.

(Example 1)

The resist RE-1 was spin-coated on a 6-inch silicon wafer. The wafer wasplaced on a hot plate heated to 90° C. The resist RE-1 was pre-baked for10 minutes, thereby forming a resist film having a thickness of 1.0 μm.Then, the resist film was pattern-exposed by means of an KrF excimerlaser (NA: 0.45), and was baked for 5 minutes on a hot plate heated to120° C. Next, the resist film was immersed in 1.59% aqueous solution oftetramethylammonium hydroxide (hereinafter abbreviated "TMAH") four 20seconds, thus developing the film. Subsequently, the resist film waswater-washed, and dried, whereby a resist pattern was formed.

(Examples 2 to 15)

The resists specified in Tables 20 and 21 were spin-coated on 6-inchsilicon wafers. The resists were pre-baked under the differentconditions--all shown in Tables 22 and 23. As a result, 14 resist films,each having a thickness of 1.0 μm, were formed on the silicon wafers.Further, each resist film was pattern-exposed by an KrF excimer-laserstepper, baked under the conditions shown in FIGS. 22 and 23. Eachresist film was then developed, washed with water, whereby 14 types ofresist patterns were formed.

The cross sections of the 15 resist patterns, thus formed, were observedby means of a scanning electronic microscope, in order to determine theresolution of each resist pattern. More precisely, the widths of thelines of the pattern and the gaps among the lines were measured. Also,the exposure amount applied to each resist film was measured. Theresults were as is shown in Tables 22 and 23, both later presented.

(Example 16)

The resist RE-1 specified in Table 20 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 10 minutes on a hot plateheated to 90° C., thereby forming a resist film having a thickness of1.0 μm, on the silicon substrate. The resist film, thus formed, waspattern-exposed by an KrF excimer-laser stepper (NA: 0.45), and wasbaked for 5 minutes on a hot plate heated to 120° C. Next, the resistfilm was immersed in 1.59% aqueous solution of TMAH for 45 seconds, thusdeveloping the film. Subsequently, the resist film was water-washed, anddried. Further, the resist film was subjected to step baking on the hotplate, being heated stepwise from 120° C. to 180° C. over 10 minutes,whereby a resist pattern was formed.

The cross section of the resist pattern, thus made, was observed bymeans of a scanning electronic microscope, in order to determine theresolution of the resist pattern. More precisely, the widths of thelines of the pattern and the gaps among the lines were measured. Also,the exposure amount applied to the resist film was measured. It wasfound that the widths of the lines and the gaps among them were 0.35 μmand that the exposure amount was 40 mJ/cm².

The resist patterns of Examples 1 and 16 were heated on a hot plate to180° C. for 5 minutes, and the cross sections of their lines having awidth of 5 μm were observed by the scanning electron microscope. It wasfound that the top of each 5 μm-wide line of Example 1 was rounded,whereas the top of each 5 μm-wide line of Example 16 remained flat.

(Example 17)

The resist RE-1 specified in Table 20 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 10 minutes on a hot plateheated to 90° C., thereby forming a resist film having a thickness of1.0 μm, on the silicon wafer. The resist film, thus formed, waspattern-exposed by an KrF excimer-laser stepper (NA: 0.45), and wasbaked for 5 minutes on a hot plate heated to 120° C. Next, the resistfilm was immersed in 1.59% aqueous solution of TMAH for 45 seconds, thusdeveloping the film. Subsequently, the resist film was water-washed, anddried. Then, the resist film was exposed to light beams havingwavelengths of 290 to 310 nm and applied from a mercury lamp through afilter for 2 minutes, while being heated to 110° C. on a hot plate in anitrogen-gas atmosphere. A resist pattern was thereby formed.

The cross section of the resist pattern, thus formed, was examined undera scanning electron microscope. It was found that the pattern had linesand gaps among these lines--all having a width of 0.35 μm. The exposureamount applied to the resist film was 40 mJ/cm².

The resist pattern of Examples 1 and 17 were heated on a hot plate to180° C. for 5 minutes, and the cross sections of its lines having awidth of 5 μm were examined by the scanning electron microscope. It wasfound that the top of each 5 μm-wide line of Example 17 remained flat,not rounded as the top of the 5 μm-wide line of Example 1.

(Example 18)

The resist RE-1 specified in Table 20 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 10 minutes on a hot plateheated to 90° C., thereby forming a resist film having a thickness of1.0 μm, on the silicon wafer. The resist film was pattern-exposed by anKrF excimer-laser stepper (NA: 0.45), and was baked for 5 minutes on ahot plate heated to 120° C. Next, the resist film was immersed in 1.59%aqueous solution of TMAH for 15 seconds, thus developed, and waswater-washed, and dried. Further, the resist film was again immersed in1.59% aqueous solution of TMAH for 15 seconds, and was water-washed, anddried, thereby forming a resist pattern.

The cross section of the resist pattern, thus formed, was examined undera scanning electron microscope. It was found that the pattern had linesand gaps among these lines--all having a width of 0.30 μm. The exposureamount applied to the resist film was 50 mJ/cm².

(Example 19)

The resist RE-1 specified in Table 20 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 10 minutes on a hot plateheated to 90° C., thereby forming a resist film having a thickness of1.0 μm, on the silicon wafer. The resist film, thus formed, waspattern-exposed by an KrF excimer-laser stepper (NA: 0.45). Then, theresist film was exposed to light beams having wavelengths of 290 to 310nm and applied from a mercury lamp through a filter for 5 minutes, whilebeing heated to 110° C. on a hot plate in a nitrogen-gas atmosphere.Next, the resist film was immersed in 1.59% aqueous solution of TMAH for45 seconds, thus developing the film. Subsequently, the resist film waswater-washed, and dried. A resist pattern was thereby formed.

The cross section of the resist pattern (Example 19) was examined undera scanning electron microscope. It was found that the pattern had linesand gaps among these lines--all having a width of 0.30 μm. The exposureamount applied to the resist film was 55 mJ/cm².

(Resist-Preparing Method 11)

First, 50 g of the acid-decomposable compound Ba-20 shown in Table 9,and 0.025 g of the acid generator C-1 specified in Table 16 (laterpresented) were dissolved in 15.8 g of ethyl cellosolve acetate, thusforming a solution. This solution was filtered by a filter having a meshsize of 0.2 μm, thus preparing a resist (hereinafter referred to as"resist RE-11").

(Resist-Preparing Methods 12 to 19)

The acid-decomposable compounds shown in Table 9, the acid generatorsspecified in Table 16, and, if necessary, an alkali-soluble polymer weremixed in the ratios specified in Tables 24 and 25 (later presented),thus forming various mixtures. The mixtures were dissolved in thesolvents shown in Tables 24 and 25 and used in the amounts specified inthese tables, too, thereby preparing 8 different solutions. Thesesolutions were filtered by a filter having a mesh size of 0.2 μm, thuspreparing 8 resists RE-12 to RE-19. Also shown in Table 24 is thecomposition of the resist RE-11.

(Example 20)

The resist RE-11 specified in Table 24 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 90 seconds minutes on a hotplate heated to 95° C., thereby forming a resist film having a thicknessof 1.0 μm, on the silicon wafer. A solution of an acidic water-solublepolymer containing methylvinyl etheranhydrous maleic acid wasspin-coated on the resist film thus formed. The polymer was baked for 60seconds on a hot plate heated to 90° C., thereby forming a polymer layerhaving a thickness of 0.15 μm. Then, the resist film was pattern-exposedby an KrF excimer-laser stepper (NA: 0.45). Next, the resist film wasbaked for 90 seconds on a hot plate heated to 95° C. Further, the filmwas washed with pure water, washing away the polymer layer. The resistfilm was then immersed in 0.14N TMAH aqueous solution for 90 seconds,thus developing the film. Subsequently, the resist film waswater-washed, and dried. A resist pattern was thereby formed.

(Examples 21 to 24)

The resists specified in Table 24 (later presented) were spin-coated on6-inch silicon wafers. The resists were pre-baked under the conditionsshown in Table 26 (later presented), thereby forming resist films offour types, each having a thickness of 1.0 μm, on the silicon wafers. Asolution of an acidic water-soluble polymer of the same type as was usedin Example 20 was spin-coated on the resist films thus formed. Thepolymer on the resist films was baked for 60 seconds on a hot plateheated to 90° C., thereby forming four polymer layers having differentthicknesses. More specifically, the layers of Examples 21, 23 and 24 hada thickness of 0.15 μm, whereas the layer of Example 22 had a thicknessof 2.0 μm. Then, the resist films were pattern-exposed, baked anddeveloped under the conditions specified in Table 26. Next, the resistfilms were washed with water and dried, whereby four types of resistpatterns were formed.

The cross sections of the resist patterns of Examples 20 to 24, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 26.As is evident from Table 26, the patterns of Examples 20 to 24 hadopenings having a rectangular cross section and had no scars on theirtops.

(Example 25)

Positive resist (OFPR 800 manufactured by Tokyo Ohka Co., Ltd.) wasspin-coated on a 6-inch silicon wafer. The resist was heated on a hotplate heated to 200° C., thereby forming a positive resist film having athickness of 2.0 μm, on the silicon wafer. Then, the resist RE-16specified in Table 26 was spin-coated on the positive resist film, thusforming a resist film having a thickness of 0.5 μm, on the positiveresist film. A solution of an acidic water-soluble polymer of the sametype as used in Example 20 was spin-coated on the resist film. Thepolymer was baked for 60 seconds on a hot plate heated to 90° C.,whereby a polymer layer having a thickness of 0.15 μm was formed.

Then, the resist film covered with the polymer layer was pattern-exposedby an KrF excimer-laser stepper (NA: 0.50). Next, the resist film waspattern-exposed at the exposure amount of 25 mJ/cm². The film, thuspattern-exposed was baked for 180 seconds on a hot plate heated to 100°C. Further, the film was washed with pure water, washing away thepolymer layer. The resist film was then immersed in 2.38% TMAH aqueoussolution for 40 seconds, thus developing the film. Subsequently, theresist film was water-washed, and dried, whereby a resist pattern wasformed.

Thereafter, the silicon wafer, with the resist pattern thus formed onits surface, was placed within a dry-etching apparatus (HiRRIEmanufactured by Tokuda Seishakusho), and the positive resist film wassubjected etching at O₂ 100 sccm, under the pressure of 6 Pa, and at thepower of 300 W. The cross section of this resist pattern was examined bya scanning electron microscope, and was found to be a fine and sharpone, having lines and gaps among the lines which were all 0.28 μm wide.

(Example 26)

The resist RE-17 specified in Table 25 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 180 seconds minutes on a hotplate heated to 90° C., thereby forming a resist film having a thicknessof 1.0 μm, on the silicon wafer. A solution of an acidic water-solublepolymer of the same type used in Example 20 was coated on the resistfilm. The polymer thus coated was baked for 60 seconds on a hot plateheated to 90° C., thereby forming a polymer layer having a thickness of0.15 μm. Then, the resist film was pattern-exposed by an KrFexcimer-laser stepper (NA: 0.45). Next, the resist film was baked for120 seconds on a hot plate heated to 120° C. Further, the film waswashed with pure water, washing away the polymer layer. The resist filmwas then immersed in 2.38% TMAH aqueous solution for 30 seconds, thusdeveloping the film. Subsequently, the resist film was water-washed, anddried, whereby a resist pattern was formed.

(Examples 27 to 30)

The resists specified in Tables 24 and 25 were spin-coated on 6-inchsilicon wafers. The resists were pre-baked under the conditions shown inTable 27 (later presented), thereby forming resist films of four types,each having a thickness of 1.0 μm, on the silicon wafers. A solution ofan acidic water-soluble polymer of the same type as was used in Example20 was spin-coated on the resist films thus formed. The polymer on theresist films was baked for 60 seconds on a hot plate heated to 90° C.,thereby forming four polymer layers having the same thicknesses of 0.14μm. Then, these resist films were pattern-exposed, baked and developedunder the conditions specified in Table 27. Next, the resist films werewashed with water and dried, whereby four types of resist patterns wereformed.

The cross sections of the resist patterns of Examples 26 to 30, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 27.As can be clearly seen from Table 27, the patterns of Examples 26 to 30had openings having a rectangular cross section and had no scars ontheir tops.

(Examples 31 to 34)

The acid-decomposable compounds, the o-quinonediazide compounds, and thealkali-soluble polymers--all specified in Table 28--were mixed, in thevarious combinations also shown in Table 28, thus forming four types ofmixtures. Each mixture was dissolved in ethyl cellosolve acetate used inthe amount specified in Table 28, too, thus preparing a solution. Thesolution was filtered by a filter having a mesh size of 0.2 μm. As aresult, four types of resists were obtained.

The resists, thus obtained, were spin-coated on 6-inch silicon wafers.The resists were pre-baked under the conditions shown in Table 29 (laterpresented), thereby forming resist films of four types, each having athickness of 1.0 μm, on the silicon wafers. Then, these resist filmswere pattern-exposed by means of an KrF excimer-laser stepper (NA:0.45), baked and developed under the conditions specified in Table 29.Next, the resist films were washed with water and dried, whereby fourtypes of resist patterns were formed.

The cross sections of the resist patterns of Examples 31 to 34, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 29.

(Examples 35 to 39)

The acid-decomposable compounds, the o-quinonediazide compounds, and thealkali-soluble polymers--all specified in Table 30--were mixed, in thevarious combinations also shown in Table 30, thus forming five types ofmixtures. Each mixture was dissolved in the solvent presented in Table30 and used in the amount specified in the same table, thus preparing asolution. The solution was filtered by a filter having a mesh size of0.2 μm. As a result, five types of resists were obtained.

The five resists, thus obtained, were spin-coated on 6-inch siliconwafers. The resists were pre-baked under the conditions shown in Table31 (later presented), thereby forming resist films of five types, eachhaving a thickness of 1.0 μm, on the silicon wafers. Then, these resistfilms were pattern-exposed by means of an KrF excimer-laser stepper (NA:0.45), baked and developed under the conditions specified in Table 31.Next, the resist films were washed with water and dried, whereby fivetypes of resist patterns were formed.

The cross sections of the resist patterns of Examples 35 to 39, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 31,too.

(Examples 40 to 42)

The acid-decomposable compounds, the acid generators, and, if necessary,the alkali-soluble polymers--all specified in Table 32--were mixed inthe various combinations also shown in Table 32, thereby preparing threetypes of mixtures. Each mixture was dissolved in ethyl cellosolveacetate used in the amount specified in Table 32, thus preparing asolution. The solutions were filtered by a filter having a mesh size of0.2 μm. As a result, three types of light-sensitive resins wereobtained.

The three resins, thus obtained, were spin-coated on 6-inch siliconwafers. The resins were pre-baked under the conditions shown in Table 33(later presented), thereby forming resist films of five types, eachhaving a thickness of 1.0 μm, on the silicon substrates. Then, theseresist films were pattern-exposed by means of an KrF excimer-laserstepper (NA: 0.45), baked and developed under the conditions specifiedin Table 32. Next, the resist films were washed with water and dried,whereby three types of resist patterns were formed.

The cross sections of the resist patterns of Examples 40 to 42, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 33,too.

(Examples 43 to 46)

The acid-decomposable compounds, the acid generators, the alkali-solublepolymers, if necessary, and the additives, if necessary--all specifiedin Table 34--were mixed in the various combinations also shown in Table34, thereby preparing four types of mixtures. Each mixture was dissolvedin ethyl cellosolve acetate used in the amount specified in Table 34,thus preparing a solution. The solution was filtered by a filter havinga mesh size of 0.2 μm. As a result, four types of resists were obtained.

The four resists, thus obtained, were spin-coated on 6-inch siliconwafers. The resists were pre-baked under the conditions shown in Table35 (later presented), thereby forming, resist films of four types, eachhaving a thickness of 1.0 μm, on the silicon wafers. Then, these resistfilms were pattern-exposed by means of an KrF excimer-laser stepper (NA:0.45), baked and developed under the conditions specified in Table 35.Next, the resist films were washed with water and dried, whereby fourtypes of resist patterns were formed.

The cross sections of the resist patterns of Examples 43 to 46, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 35.

(Example 47)

First, 9.5 g of the acid-decomposable compound Ba-25 specified in Table9 and 0.5 g of 1-naphthoquinone-2-diazo-4-ester sulfonate ofp-cyanophthalate were dissolved in 40 g of ethyl-3-ethoxypropionate,thus forming a solution. This solution was filtered by a filter having amesh size of 0.2 μm, whereby a resist was prepared.

The resist, thus prepared, was spin-coated on a 6-inch silicon wafer.The resist was pre-baked for 3 minutes on a hot plate heated to 90° C.,thereby forming a resist film having a thickness of 1.0 μm, on thesilicon wafer. Then, the resist film was pattern-exposed by means of ani-line stepper (NA: 0.50), baked for 2 minutes on a hot plate heated to110° C. Next, the resist film was immersed in 2.38% TMAH aqueoussolution for 30 seconds, thus developing the film. Subsequently, theresist film was water-washed, and dried, whereby a resist pattern wasformed.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.40 μm wide. It should be noted that the resistfilm had been pattern-exposed at the exposure amount of 50 mJ/cm².

(Example 48)

First, 4.0 g of the acid-decomposable compound Ba-25 specified in Table9 and 0.21 g of 1-naphthoquinone-2-diazide-4-ester sulfonate of4,4'-dihydroxy diphenylsulfide, (esterification number: 3 per molecule)were dissolved in 12.6 g of ethyl-3-ethoxypropionate, thus forming asolution. This solution was filtered by a filter having a mesh size of0.2 μm, whereby a resist was obtained. This resist was processed by thesame method as Example 47, thus forming a resist pattern.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.40 μm wide. It should be noted that the resistfilm had been pattern-exposed at the exposure amount of 65 mJ/cm².

(Example 49)

First, 4.0 g of the acid-decomposable compound Ba-30 shown in Table 9and 0.21 g of 1-naphthoquinone-2-diazide-4-ester sulfonate of2,4-dihydroxy diphenyl sulfide, (esterification number: 1.5 permolecule) were dissolved in 12.5 g of ethyl cellosolve acetate,preparing a solution. This solution was filtered by a filter having amesh size of 0.2 μm, whereby a resist was obtained.

The resist, thus obtained, was spin-coated on a 6-inch silicon wafer.The resist was pre-baked for 3 minutes on a hot plate heated to 90° C.,thereby forming a resist film having a thickness of 1.0 μm, on thesilicon wafer. Then, the resist film was pattern-exposed by means of anKrF excimer-laser stepper (NA: 0.45), baked for 2 minutes on a hot plateheated to 120° C. Next, the resist film was immersed in 2.38% TMAHaqueous solution for 30 seconds, thus developing the film. Subsequently,the resist film was water-washed, and dried, whereby a resist patternwas formed.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.35 μm wide. It should be noted that the resistfilm had been pattern-exposed at the exposure amount of 75 mJ/cm².

(Example 50)

First, 4.0 g of the acid-decomposable compound Ba-25 specified in Table9 and 0.20 g of 1-naphthoquinone-2-diazide-4-ester sulfonate of3,4,5-trihydoxy methylbenzoate (esterification number: 3 per molecule)were dissolved in 12.5 g of ethyl lactate, thus preparing a solution.This solution was filtered by a filter having a mesh size of 0.2 μm,whereby a resist was obtained. This resist was processed by the samemethod as Example 49, thus forming a resist pattern.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.35 μm wide. It should be noted that the resistfilm had been pattern-exposed at the exposure amount of 85 mJ/cm².

(Example 51)

First, 4.0 g of the acid-decomposable compound Ba-25 shown in Table 9,0.22 g of the o-quinonediazide compound QD-4, and 0.22 g of theo-quinonediazide compound QD-5, both o-quionediazide compounds specifiedin Table 1 and the same esterification number of 3 per molecule, weredissolved in 13.5 g of ethyl cellosolve acetate, thus preparing asolution. This solution was filtered by a filter having a mesh size of0.2 μm, whereby a resist was obtained.

The resist, thus formed, was spin-coated on a 6-inch silicon wafer. Theresist was pre-baked for 3 minutes on a hot plate heated to 90° C.,thereby forming a resist film having a thickness of 1.0 μm, on thesilicon wafer. Then, the resist film was pattern-exposed by means of anKrF excimer-laser stepper (NA: 0.50), baked for 90 seconds on a hotplate heated to 110° C. Next, the resist film was immersed in 2.38% TMAHaqueous solution for 30 seconds, thus developing the film. Subsequently,the resist film was water-washed, and dried, whereby a resist patternwas formed.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.35 μm wide. It should be noted that the resistfilm had been pattern-exposed at the exposure amount of 100 mJ/cm².

(Example 52)

First, 4.0 g of the acid-decomposable compound Ba-35 shown in Table 9,0.20 g of diphenyliodonium trifluoromethane sulfonate, and 0.13 g of4-hydroxy benzoic acid were dissolved in 13 g of ethyl cellosolveacetate, preparing a solution. The solution, was filtered by a filterhaving a mesh size of 0.2 μm, whereby a resist was obtained.

The resist, thus obtained, was spin-coated on a 6-inch silicon wafer.The resist was pre-baked for 5 minutes on a hot plate heated to 90° C.,thereby forming a resist film having a thickness of 1.0 μm, on thesilicon wafer. Then, the resist film was pattern-exposed by means of anKrF excimer-laser stepper (NA: 0.41), baked for 3 minutes on a hot plateheated to 100° C. Next, the resist film was immersed in 2.38% TMAHaqueous solution for 30 seconds, thus developing the film. Subsequently,the resist film was water-washed, and dried, whereby a resist patternwas formed.

The cross section of the resist pattern, thus formed, was examined undera scanning electron microscope, and was found to have lines and gapsamong the lines which were all 0.35 μm wide. It should be noted that theresist film had been pattern-exposed at the exposure amount of 30mJ/cm². As is evident from FIG. 1, the the pattern of Examples 52 had nohardly soluble layers having scars, and was a fine resist pattern.

(Comparative Example)

First, 5 g of an acid-decomposable compound B-12 shown in Table 14 and0.05 g of an acid generator C-2 shown in Table 16 were dissolved in 15 gof ethyl cellosolve acetate, thus preparing a solution. This solutionwas filtered by a filter having a mesh size of 0.2 μm, whereby a resistwas obtained. The resist was processed by the same method as Example 52,thus forming a resist pattern.

The cross section of the resist pattern, thus formed, was examined undera scanning electron microscope, and was found to have lines and gapsamong the lines which were all 0.40 μm wide. It should be noted that theresist film had been pattern-exposed at the exposure amount of 25mJ/cm². As is evident from FIG. 2, the the pattern 2 of the ComparativeExample had a hardly soluble layer 3 having scars

(Example 53)

First, 3.0 g of the acid-decomposable compound Ba-25 shown in Table 9,0.44 g of o-quinonediazide compound QD-4 shown in Table 1, in whichnumber of Xs is 3 per molecule, 1.0 g of polyvinyl phenol, and 0.25 g ofacetic acid were dissolved in 13.8 g of ethyl cello solve acetate, thuspreparing a solution. The solution was filtered by a filter having amesh size of 0.2 μm, thereby obtaining a resist.

The resist was spin-coated on a 6-inch silicon wafer. The resist waspre-baked for 3 minutes on a hot plate heated to 90° C., thereby forminga resist film having a thickness of 1.0 μm, on the silicon wafer. Then,the resist film was pattern-exposed by means of an KrF excimer-laserstepper (NA: 0.42), baked for 2 minutes on a hot plate heated to 120° C.Next, the resist film was immersed in 2.38% TMAH aqueous solution for 30seconds, thus developing the film. Subsequently, the resist film waswater-washed, and dried, whereby a resist pattern was formed.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.30 μm wide. It should be noted that the resistfilm had been pattern-exposed at the exposure amount of 50 mJ/cm².

(Example 54)

A resist of the same type as Example 53 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 3 minutes on a hot plateheated to 90° C., thereby forming a resist film having a thickness of1.0 μm, on the silicon wafer. Then, the resist film was pattern-exposedby means of an i-line stepper (1505i7A manufactured by Nicon Co., Ltd),baked for 1 minutes on a hot plate heated to 120° C. Next, the resistfilm was immersed in 2.38% TMAH aqueous solution for 30 seconds, thusdeveloping the film. Subsequently, the resist film was water-washed, anddried, whereby a resist pattern was formed.

The cross section of the resist pattern was examined under a scanningelectron microscope, and was found to have lines and gaps among thelines which were all 0.40 μm wide. It should be noted that the resistfilm had been pattern-exposed for a period of 10 msec.

(Examples 55 to 58)

The acid-decomposable compounds, the acid generators, the alkali-solublepolymers, if necessary, and the carboxylic acids--all specified in Table36--were mixed in the various combinations also shown in Table 36,thereby preparing four types of mixtures. Each mixture was dissolved inethyl cello solve acetate used in the amount specified in Table 36, thuspreparing four solutions. The solution was filtered by a filter having amesh size of 0.2 μm. As a result, four types of resists were obtained.

The four resists were spin-coated on 6-inch silicon wafers. The resistswere pre-baked under the conditions shown in Table 37, thereby formingresist films of four types, on the silicon substrates. Then, theseresist films were pattern-exposed by means of an KrF excimer-laserstepper (NA: 0.45), baked and developed under the conditions specifiedin Table 37. Next, the resist films were washed with water and dried,whereby four types of resist patterns were formed.

The cross sections of the resist patterns of Examples 55 to 58, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 37.

(Examples 59 to 62)

The acid-decomposable compounds, the acid generators, the alkali-solublepolymers, if necessary, and the carboxylic acids--all specified in Table38--were mixed in the various combinations also shown in Table 38,thereby preparing four types of mixtures. Each mixture was dissolved inthe solvents specified in Table 38 and used in the amount specified inTable 38, thus preparing four solutions. The solutions were filtered bya filter having a mesh size of 0.2 μm. As a result, four types ofresists were obtained.

The four resists, thus obtained, were spin-coated on 6-inch siliconwafers. The resists were pre-baked under the conditions shown in Table39, thereby forming resist films of four types, on the silicon wafers.Then, these resist films were pattern-exposed by means of an KrFexcimer-laser stepper (NA: 0.45), baked and developed under theconditions specified in Table 39. Next, the resist films were washedwith water and dried, whereby four types of resist patterns were formed.

The cross sections of the resist patterns of Examples 59 to 62, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Table 39,too.

The resist patterns of Examples 55 to 62 had each openings having arectangular cross section and had no scars on their tops.

(Resist-Preparing Method 21)

First, 5.0 g of the acid-decomposable compound Ba-20 specified in Table9, 0.025 g of the strong acid generator C-1 shown in Table 16, and 0.56g of the weak acid generator D-2 specified in Table 18 were dissolved in16.7 g of ethyl lactate, preparing a solution. The solution was filteredby a filter having a mesh size of 0.2 μm, whereby a resist RE-21 wasprepared.

(Resist-Preparing Methods 22 to 30)

The acid-decomposable compounds shown in Table 9, the strong acidgenerators specified in Table 16, the weak acid generators specified inTable 18, and, if necessary, the alkali-soluble polymers shown in Tables40 and 41 and used in the amounts specified in Tables 40 and 41, weremixed, forming nine mixtures. These mixtures were dissolved in thevarious solvents shown in Tables 40 and 41 and used in the amounts alsoshown in Tables 40 and 41, preparing nine solutions. These solutionswere filtered by a filter having a mesh size of 0.2 μm, whereby nineresists RE-22 to RE-30 were obtained. The composition of the resistRE-21 is also presented in Table 40.

(Example 63)

The resist RE-21 specified in Table 40 was spin-coated on a 6-inchsilicon wafer. The resist was pre-baked for 90 seconds on a hot plateheated to 90° C., thereby forming a resist film having a thickness of1.0 μm, on the silicon wafer. Then, the resist film was pattern-exposedby means of an KrF excimer-laser stepper (NA: 0.42), baked for 90seconds on a hot plate heated to 95° C. Next, the resist film wasimmersed in 1.19% TMAH aqueous solution for 90 seconds, thus developingthe film. Subsequently, the resist film was water-washed, and dried,whereby a resist pattern was formed.

(Examples 64 to 71)

The resists specified in Tables 40 and 41 were spin-coated on 6-inchsilicon wafers. The resists were pre-baked under the conditions shown inTables 42 and 43, thereby forming resist films of eight types, on thesilicon wafers. Then, these resist films were pattern-exposed, baked anddeveloped under the conditions specified in Tables 42 and 43. The resistfilms were washed with water and dried, whereby eight types of resistpatterns were formed.

The cross sections of the resist patterns of Examples 63 to 71, thusformed, were examined under a scanning electron microscope, measuringthe widths of the lines forming each pattern and gaps among these lines.Also the exposure amounts applied to the resist films to form the resistpatterns were detected. The results were as is represented in Tables 42and 43, too.

(Example 72)

A positive resist (OFPR 800 manufactured by Tokyo Ohyoka Co., Ltd.) wasspin-coated on a 6-inch silicon wafer. The resist was pre-baked for 30minutes on a hot plate heated to 200° C., thereby forming a positiveresist film having a thickness of 2.0 μm, on the silicon wafer. Further,the resist RE-30 specified in Table 41 was spin-coated on the positiveresist film, forming a resist film having a thickness of 0.5 μm. Then,the resist film was pattern-exposed by means of an i-line stepper (NA:0.50) at exposure amount of 45 mJ/cm², baked for 180 seconds on a hotplate heated to 100° C. Next, the resist film was immersed in 2.38% TMAHaqueous solution for 40 seconds, thus developing the film. Subsequently,the resist film was water-washed, and dried, whereby a resist patternwas formed.

Thereafter, the silicon wafer, with the resist pattern thus formed onits surface, was placed within a dry-etching apparatus (HiRRIEmanufactured by Tokuda Seishakusho), and the positive resist film wassubjected to etching at O₂ 100 sccm, under the pressure of 6 Pa, and atthe power of 300 W. The cross section of this resist pattern wasexamined by a scanning electron microscope, and was found to be a fineand sharp one, having lines and gaps among the lines which were all 0.35μm wide.

As has been described, the present invention can provide a resist whichis greatly sensitive to ultraviolet rays (preferably, deep-UV) or anionizing radiation, and which can therefore form a high-resolutionresist pattern if exposed to ultraviolet rays or an unionizingradiation. Also, the invention can provide a method of manufacturingfine resist patterns, each having openings having a rectangular crosssection. Thus, the resist can be useful to the manufacture ofsemiconductor devices having high integration densities.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details, and representative resist shown anddescribed herein. Accordingly, various modifications may be made withoutdeparting from the spirit or scope of the general inventive concept asdefined by the appended claims and their equivalents.

                  TABLE 1                                                         ______________________________________                                         ##STR3##                    (QD-1)                                            ##STR4##                    (QD-2)                                            ##STR5##                    (QD-3)                                            ##STR6##                    (QD-4)                                            ##STR7##                    (QD-5)                                            ##STR8##                    (QD-6)                                           wherein,                                                                       ##STR9##                                                                     ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                         ##STR10##                  (QD-7)                                             ##STR11##                  (QD-8)                                             ##STR12##                  (QD-9)                                             ##STR13##                  (QD-10)                                            ##STR14##                  (QD-11)                                            ##STR15##                  (QD-12)                                           wherein,                                                                       ##STR16##                                                                    ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                         ##STR17##                  (QD-13)                                            ##STR18##                  (QD-14)                                            ##STR19##                  (QD-15)                                                                       (QD-16)                                            ##STR20##                                                                    wherein,                                                                       ##STR21##                                                                    ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                         ##STR22##                  (QD-17)                                            ##STR23##                  (QD-18)                                            ##STR24##                  (QD-19)                                            ##STR25##                  (QD-20)                                            ##STR26##                  (QD-21)                                            ##STR27##                  (QD-22)                                           wherein,                                                                       ##STR28##                                                                    ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                         ##STR29##                  (QD-23)                                            ##STR30##                  (QD-24)                                            ##STR31##                  (QD-25)                                            ##STR32##                  (QD-26)                                           wherein,                                                                       ##STR33##                                                                    ______________________________________                                    

TABLE 6

(Alkali-soluble polymer)

J-1 Poly-p-vinylphenol

J-2 Poly-o-vinylphenol

J-3 Poly-m-isopropenylphenol

J-4 m, p-cresol novolac resin

J-5 xylesol movolac resin

J-6 p-vinylphenol-methyl methacrylate copolymer

J-7 p-isopropenylphenol-maleic anhydride copolymer

J-8 polymethacrylic acid

J-9; Poly-p-hydroxystyrene

                  TABLE 7                                                         ______________________________________                                        (Alkali-soluble polymer)                                                      ______________________________________                                        J-10;                                                                               ##STR34##                                                               J-11;                                                                               ##STR35##                                                               J-12;                                                                               ##STR36##                                                               J-13;                                                                               ##STR37##                                                               J-14;                                                                               ##STR38##                                                               ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        (Alkali-soluble polymer)                                                      ______________________________________                                        J-15;                                                                               ##STR39##                                                               J-16;                                                                               ##STR40##                                                               J-17;                                                                               ##STR41##                                                                J-18;                                                                         ##STR42##                                                                    ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        (Acid-decomposable compounds)                                                  ##STR43##                                                                    Acid-decomposable                                                             Compound         n/(m + n)                                                    ______________________________________                                        Ba - 17          0.17                                                         Ba - 20          0.20                                                         Ba - 25          0.25                                                         Ba - 30          0.30                                                         Ba - 35          0.35                                                         Ba - 42          0.42                                                         Ba - 60          0.60                                                         ______________________________________                                    

                  TABLE 10                                                        ______________________________________                                        (Acid-decomposable compounds)                                                  ##STR44##                                                                    Acid-decomposable                                                             Compound         n/(m + n)                                                    ______________________________________                                        Ba - 20          0.20                                                         Ba - 25          0.25                                                         ______________________________________                                    

                  TABLE 11                                                        ______________________________________                                        (Acid-decomposable compounds)                                                 ______________________________________                                         ##STR45##                    (B-1)                                            ##STR46##                    (B-2)                                            ##STR47##                    (B-3)                                            ##STR48##                    (B-4)                                           ______________________________________                                    

                                      TABLE 12                                    __________________________________________________________________________    (Acid-decomposable compounds)                                                 __________________________________________________________________________     ##STR49##                           (B-5)                                     ##STR50##                           (B-6)                                     ##STR51##                           (B-7)                                    __________________________________________________________________________

                  TABLE 13                                                        ______________________________________                                        (Acid-decomposable compounds)                                                 ______________________________________                                         ##STR52##                    (B-8)                                            ##STR53##                    (B-9)                                           ______________________________________                                    

                  TABLE 14                                                        ______________________________________                                        (Acid-decomposable compounds)                                                 ______________________________________                                         ##STR54##                   (B-10)                                            ##STR55##                   (B-11)                                            ##STR56##                   (B-12)                                           ______________________________________                                    

                  TABLE 15                                                        ______________________________________                                        (Acid-decomposable compounds)                                                 ______________________________________                                         ##STR57##                   (B-13)                                            ##STR58##                   (B-14)                                           ______________________________________                                    

TABLE 16

(Acid(strong acid)-generating compounds)

C-1; Triphenylsulfonium trifluoromethanesulfonate

C-2; Diphenyliodonium trifluoromethanesulfonate

C-3; 2,3,4,4'-tetra hydroxybenzophenone1,2-naphthoquinone-diazide-4-sulfonic acid ester (average esterificationnumber: 3 per molecule)

C-4; P-toluenesulfonic acid-2,6-dinitrobenzyl ester

C-5; Bis(phenylsulfonyl)methane

C-6; Bis(phenylfonyl)diazomethane

C-7; Bis(4-tert butylphenyl)iodonium trifluoromethane sulfonate

C-8; Tert-butyl-d(p-toluenesalfonyloxy)acetate

                  TABLE 17                                                        ______________________________________                                        Acid (strong acid)-generating compounds                                       ______________________________________                                         ##STR59##                                                                     ##STR60##                                                                    ______________________________________                                    

                  TABLE 18                                                        ______________________________________                                        (Weak acid-generating compounds)                                              ______________________________________                                         ##STR61##                                                                    D-2;5-diazo meldrum's acid                                                     ##STR62##                                                                     ##STR63##                                                                     ##STR64##                                                                     ##STR65##                                                                    ______________________________________                                    

                  TABLE 19                                                        ______________________________________                                        (Additives)                                                                   ______________________________________                                         ##STR66##                   (W-1)                                             ##STR67##                   (W-2)                                             ##STR68##                   (W-3)                                            ______________________________________                                    

                                      TABLE 20                                    __________________________________________________________________________    Composition of the Resist                                                                      O-quinoneazide                                                   Acid-Decomposable                                                                          (Tables 1 and 4)                                                 Compound (Table 9)                                                                         and Amount                                                                            Amount of  Solvent and                               Resist                                                                            and Amount Thereof Used                                                                    Thereof Used                                                                          Polyvinylphenol Used                                                                     Amount Thereof Used                       __________________________________________________________________________    RE-1                                                                              Ba-35        QD-4    2.0 g      Ethyl Cellosolve                              (2.0 g)      (0.44 g)           Acetate (13.8 g)                          RE-2                                                                              Ba-35        QD-4    2.0 g      Ethyl Cellosolve                              (2.0 g)      (0.21 g)           Acetate (13.8 g)                          RE-3                                                                              Ba-25        QD-1    2.0 g      Ethyl Cellosolve                              (2.0 g)      (0.44 g)           Acetate (14.0 g)                          RE-4                                                                              Ba-25        QD-4    1.3 g      Ethyl Cellosolve                              (2.7 g)      (0.44 g)           Acetate (14.0 g)                          RE-5                                                                              Ba-25         QD-20  1.3 g      Ethyl Cellosolve                              (2.7 g)      (0.44 g)           Acetate (14.0 g)                          __________________________________________________________________________

                                      TABLE 21                                    __________________________________________________________________________    Composition of the Resist                                                                      O-quinoneazeide                                                  Acid-Decomposable                                                                          (Tables 1, 3 and 5)                                              Compound (Table 9)                                                                         and Amount                                                                              Amount of  Solvent and                             Resist                                                                            and Amount Thereof Used                                                                    Thereof Used                                                                            Polyvinylphenol Used                                                                     Amount Thereof Used                     __________________________________________________________________________    RE-6                                                                              Ba-25        QD-18     1.0 g      Ethyl   Cellosolve                          (3.0 g)      (0.25 g)             Acetate (14.0 g)                        RE-7                                                                              Ba-17        QD-4      --         Ethyl   Cellosolve                          (4.0 g)      (0.44 g)             Acetate (14.0 g)                        RE-8                                                                              Ba-35        QD-4      2.0 g      ECA-NMP*                                                                              (14.0 g)                            (2.0 g)      (0.21 g)                                                     RE-9                                                                              Ba-42        QD-23     2.4 g      Ethyl Lactate                                                                         (15.0 g)                            (1.6 g)      (0.60 g)                                                     RE-10                                                                             Ba-20        QD-15     --         Cyclohexanone                                                                         (16.0 g)                            (2.7 g)      (0.70 g)                                                     __________________________________________________________________________     ECA-NMP* is a mixture solvent of ethylcellosolveacetate and                   Nmethylprolidone (vol. ratio: 0.95:0.05)                                 

                                      TABLE 22                                    __________________________________________________________________________                    Exposure        TMAH Solution                                          Pre-Baking                                                                           Amount                                                                             Post-Exposure                                                                            Concentration &                                                                         Resolution                          Example                                                                            Resist                                                                            Temp., Time                                                                          (mJ/cm.sup.2)                                                                      Baking Temp. & Time                                                                      Development Time                                                                        (μm)                             __________________________________________________________________________    1    RE-1                                                                               90° C.                                                                       40   120° C.                                                                           1.59%     0.35                                         10 min.     5 min.     20 sec.                                       2    RE-1                                                                              100° C.                                                                       60   120° C.                                                                           1.19%     0.35                                         3 min.      3 min.     90 sec.                                       3    RE-2                                                                               90° C.                                                                       120  110° C.                                                                           2.38%     0.40                                         2 min.      2 min.     30 sec.                                       4    RE-3                                                                               90° C.                                                                       72   130° C.                                                                           1.59%     0.40                                         5 min.      1 min.     30 sec.                                       5    RE-4                                                                              100° C.                                                                       50   120° C.                                                                           1.19%     0.30                                         3 min.      3 min.     40 sec.                                       6    RE-5                                                                              100° C.                                                                       100  120° C.                                                                           1.19%     0.35                                         3 min.      3 min.     60 sec.                                       7    RE-6                                                                              100° C.                                                                       65   120° C.                                                                           1.19%     0.35                                         3 min.      3 min.     60 sec.                                       8    RE-7                                                                               90° C.                                                                       80   120° C.                                                                           1.19%     0.35                                         2 min.      5 min.     56 sec.                                       __________________________________________________________________________

                                      TABLE 23                                    __________________________________________________________________________                    Exposure        TMAH Solution                                          Pre-Baking                                                                           Amount                                                                             Post-Exposure                                                                            Concentration &                                                                         Resolution                          Example                                                                            Resist                                                                            Temp., Time                                                                          (mJ/cm.sup.2)                                                                      Baking Temp. & Time                                                                      Development Time                                                                        (μm)                             __________________________________________________________________________     9   RE-8                                                                              100° C.                                                                       78   120° C.                                                                           1.19%     0.35                                         3 min.      3 min.     50 sec.                                       10   RE-9                                                                               90° C.                                                                       120  110° C.                                                                           1.59%     0.40                                         2 min.      2 min.     50 sec.                                       11    RE-10                                                                             80° C.                                                                       130  120° C.                                                                           2.38%     0.40                                         5 min.      5 min.     40 sec.                                       12   RE-1                                                                              110° C.                                                                       40   120° C.                                                                           1.19%     0.30                                         3 min.      3 min.     40 sec.                                       13   RE-2                                                                              100° C.                                                                       80   120° C.                                                                           2.38%     0.35                                         3 min.      3 min.     90 sec.                                       14   RE-4                                                                              110° C.                                                                       25   120° C.                                                                           1.19%     0.30                                         3 min.      3 min.     40 sec.                                       15   RE-8                                                                              110° C.                                                                       60   120° C.                                                                           1.19%     0.35                                         3 min.      3 min.     50 sec.                                       __________________________________________________________________________

                                      TABLE 24                                    __________________________________________________________________________    Composition of the Resist                                                         Acid-Decomposable       Alkali-Soluble                                        Compound (Table 9)                                                                         Acid Generator                                                                           Polymer and                                                                            Solvent and                              Resist                                                                            and Amount Thereof Used                                                                    and Amount Thereof                                                                       Amount Thereof                                                                         Amount Thereof Used                      __________________________________________________________________________    RE-11                                                                             Ba-20        C-1 (Table 16)                                                                           --       Ethyl  Cellosolve                            (5.0 g)      (0.025 g)           Acetate                                                                              (15.8 g)                          RE-12                                                                             Ba-35        C-1 (Table 16)                                                                           J-9 (Table 6)                                                                          Ethyl  Cellosolve                            (4.5 g)      (0.25 g)   (1.5 g)  Acetate                                                                              (18.8 g)                          RE-13                                                                             Ba-25        C-2 (Table 16)                                                                           --       Ethyl Lactate                                                                        (18.0 g)                              (6.0 g)      (0.05 g)                                                     RE-14                                                                             Ba-20        C-3 (Table 16)                                                                           --       Ethyl Lactate                                                                        (19.0 g)                              (6.0 g)      (0.30 g)                                                     RE-15                                                                             Ba-25        C-3 (Table 16)                                                                           J-4 (Table 6)                                                                          Ethyl Lactate                                                                        (31.5 g)                              (6.0 g)      (0.50 g)   (4.0 g)                                           __________________________________________________________________________

                                      TABLE 25                                    __________________________________________________________________________    Composition of the Resist                                                         Acid-Decomposable       Alkali-Soluble                                        Compound (Table 9)                                                                         Acid Generator                                                                           Polymer and                                                                            Solvent and                              Resist                                                                            and Amount Thereof Used                                                                    and Amount Thereof                                                                       Amount Thereof                                                                         Amount Thereof Used                      __________________________________________________________________________    RE-16                                                                             Ba-35        C-3 (Table 16)                                                                           J-13 (Table 7)                                                                         Ethyl Cellosolve                             (5.0 g)      (1.00 g)   (5.0 g)  Acetate (45.0 g)                         RE-17                                                                             Ba-20        C-4 (Table 16)                                                                           J-9 (Table 6)                                                                          Ethyl Cellosolve                             (8.0 g)      (0.50 g)   (2.0 g)  Acetate (31.5 g)                         RE-18                                                                             Ba-20        C-5 (Table 16)                                                                           --       Ethyl Cellosolve                             (4.85 g)     (0.15 g)            Acetate (15.0 g)                         RE-19                                                                             Ba-20        C-5 (Table 16)                                                                           --       Ethyl Cellosolve                             (4.75 g)     (0.25 g)            Acetate (15.0 g)                         __________________________________________________________________________

                                      TABLE 26                                    __________________________________________________________________________                                        TMAH Solution                                                                           Exposure                                 Pre-Baking                                                                           Exposure Post-Exposure                                                                            Concentration &                                                                         Amount                                                                             Resolution                 Example                                                                            Resist                                                                            Conditions                                                                           Condition                                                                              Baking Temp. & Time                                                                      Development Time                                                                        (mJ/cm.sup.2)                                                                      (μm)                    __________________________________________________________________________    20   RE-11                                                                             95° C.                                                                        KrF Excimer                                                                            95° C.                                                                            0.14N     30   0.25                                 90 sec.                                                                             Laser                                                                             (NA0.45)                                                                           90 sec.    90 sec.                                   21   RE-12                                                                             90° C.                                                                        KrF Excimer                                                                            95° C.                                                                            0.14N     45   0.30                                120 sec.                                                                             Laser                                                                             (NA0.45)                                                                           90 sec.    60 sec.                                   22   RE-13                                                                             95° C.                                                                        KrF Excimer                                                                            80° C.                                                                            0.14N     25   0.30                                 90 sec.                                                                             Laser                                                                             (NA0.45)                                                                           120 sec.   50 sec.                                   23   RE-14                                                                             90° C.                                                                        i-line                                                                            (NA0.50)                                                                           105° C.                                                                           0.14N     50   0.35                                300 sec.        120 sec.   30 sec.                                   24   RE-15                                                                             95° C.                                                                        i-line                                                                            (NA0.50)                                                                           95° C.                                                                            2.38%     100  0.40                                120 sec.        90 sec.    30 sec.                                   __________________________________________________________________________

                                      TABLE 27                                    __________________________________________________________________________                                       TMAH Solution                                                                           Exposure                                  Pre-Baking                                                                           Exposure                                                                              Post-Exposure                                                                            Concentration &                                                                         Amount                                                                             Resolution                  Example                                                                            Resist                                                                            Conditions                                                                           Condition                                                                             Baking Temp. & Time                                                                      Development Time                                                                        (mJ/cm.sup.2)                                                                      (μm)                     __________________________________________________________________________    26   RE-17                                                                             90° C.                                                                        KrF Excimer                                                                           120° C.                                                                           2.38%     20   0.35                                 180 sec.                                                                             Laser (NA0.45)                                                                        120 sec.   30 sec.                                    27   RE-14                                                                             95° C.                                                                        KrF Excimer                                                                            95° C.                                                                           0.14N     60   0.30                                 90 sec.                                                                              Laser (NA0.45)                                                                         90 sec.   50 sec.                                    28   RE-18                                                                             95° C.                                                                        KrF Excimer                                                                           100° C.                                                                           0.14N     40   0.35                                 90 sec.                                                                              Laser (NA0.45)                                                                        120 sec.   30 sec.                                    29   RE-14                                                                             95° C.                                                                        KrF Excimer                                                                           105° C.                                                                           0.14N     50   0.30                                 90 sec.                                                                              Laser (NA0.45)                                                                         90 sec.   50 sec.                                    30   RE-19                                                                             95° C.                                                                        KrF Excimer                                                                           110° C.                                                                           0.14N     70   0.35                                 90 sec.                                                                              Laser (NA0.45)                                                                        120 sec.   50 sec.                                    __________________________________________________________________________

                                      TABLE 28                                    __________________________________________________________________________    Composition of the Resist                                                                    O-quinonediazide                                                                         Alkali-Soluble                                                                           Amount of                                     Acid Generator and                                                                      (Tables 1 and 4)                                                                         Polymer and Amount                                                                       Ethyl Cellosolve                         Example                                                                            Amount Thereof                                                                          and Amount Thereof                                                                       Thereof Used                                                                             Acetate                                  __________________________________________________________________________    31   B-1 (Table 11)                                                                          QD-4        J-4 (Table 6)                                                                           37.0 g                                        (2.0 g)    (1.0 g)   (8.0 g)                                             32   B-2 (Table 11)                                                                          QD-4        J-1 (Table 6)                                                                           14.0 g                                        (1.0 g)   (0.44 g)   (3.0 g)                                             33   B-3 (Table 11)                                                                          QD-1       J-13 (Table 7)                                                                           18.0 g                                        (2.0 g)   (0.44 g)   (3.0 g)                                             34   B-4 (Table 11)                                                                          QD-4       J-13 (Table 7)                                                                           14.0 g                                        (1.0 g)   (0.44 g)   (3.0 g)                                             __________________________________________________________________________

                                      TABLE 29                                    __________________________________________________________________________                Exposure        TMAH Solution                                          Pre-Baking                                                                           Amount                                                                             Post-Exposure                                                                            Concentration &                                                                         Resolution                              Example                                                                            Temp., Time                                                                          (mJ/cm.sup.2)                                                                      Baking Temp. & Time                                                                      Development Time                                                                        (μm)                                 __________________________________________________________________________    31   100° C.                                                                       80   120° C.                                                                           2.38%     0.35                                         3 min.      5 min.     40 sec.                                           32   100° C.                                                                       70   120° C.                                                                           1.59%     0.35                                         3 min.      3 min.     30 sec.                                           33   100° C.                                                                       60   120° C.                                                                           1.59%     0.25                                         3 min.      3 min.     60 sec.   Initial Thickness;                                                              0.50 μm                            34   100° C.                                                                       75   100° C.                                                                           2.38%     0.25                                         3 min.      5 min.     50 sec.   Initial Thickness;                                                              0.50 μm                            __________________________________________________________________________

                                      TABLE 30                                    __________________________________________________________________________    Composition of the Resist                                                                    O-quinonediazide                                                                         Alkali-Soluble                                           Acid Generator and                                                                      (Tables 1 and 3 to 5)                                                                    Polymer and                                                                              Solvent and                              Example                                                                            Amount Therof                                                                           and Amount Thereof                                                                       Amount Thereof Used                                                                      Amount Thereof                           __________________________________________________________________________    35   B-5 (Table 12)                                                                          OD-4 (0.5 g)                                                                             J-1 (Table 6)                                                                            Ethyl  Cellosolve                             (8.0 g)   QD-23 (0.5 g)                                                                            (2.0 g)    Acetate                                                                              (35 g)                            36   B-6 (Table 12)                                                                          QD-18      J-1 (Table 6)                                                                            N-methyl-2-                                                                          (33 g)                                 (2.0 g)   (1.0 g)    (7.0 g)    pyrrolidone                              37   B-7 (Table 12)                                                                          QD-4       J-7 (Table 6)                                                                            Ethyl  Cellosolve                             (2.5 g)   (1.0 g)    (6.5 g)    Acetate                                                                              (31 g)                            38   B-8 (Table 13)                                                                          QD-20      J-5 (Table 6)                                                                            Ethyl  Cellosolve                             (1.0 g)   (0.8 g)    (6.0 g)    Acetate                                                                              (34 g)                            39   B-9 (Table 13)                                                                          QD-16      J-4 (Table 6)                                                                            Ethyl  Cellosolve                             (1.0 g)   (1.0 g)    (6.0 g)    Acetate                                                                              (32 g)                            __________________________________________________________________________

                                      TABLE 31                                    __________________________________________________________________________                Exposure        TMAH Solution                                          Pre-Baking                                                                           Amount                                                                             Post-Exposure                                                                            Concentration &                                                                         Resolution                              Example                                                                            Temp., Time                                                                          (mJ/cm.sup.2)                                                                      Baking Temp. & Time                                                                      Development Time                                                                        (μm)                                 __________________________________________________________________________    35   100° C.                                                                       110  120° C.                                                                           1.59%     0.35                                         3 min.      5 min.     40 sec.                                           36   110° C.                                                                       150  150° C.                                                                           2.38%     0.50                                         3 min.      1 min.     40 sec.                                           37   120° C.                                                                       100  130° C.                                                                           1.59%     0.45                                         3 min.      2 min.     50 sec.                                           38    90° C.                                                                        80  125° C.                                                                           2.38%     0.40                                         5 min.      5 min.     50 sec.                                           39    90° C.                                                                       130  125° C.                                                                           2.38%     0.40                                         10 min.     3 min.     50 sec.                                           __________________________________________________________________________

                                      TABLE 32                                    __________________________________________________________________________    Composition of the Resist                                                          Acid-Decomposable    Alkali-Soluble                                           Compound and                                                                            Acid Generator                                                                           Polymer and                                                                            Additive and                                                                           Amount of                         Example                                                                            Amount Thereof                                                                          and Amount Thereof                                                                       Amount Thereof                                                                         Amount Thereof                                                                         ECA* (Solvent)                    __________________________________________________________________________    40   Ba-25 (Table 9)                                                                         QD-4 (Table 1)                                                                           J-1 (Table 6)                                                                          --       35 g                                   (8.3 g)   (0.5 g)    (7.5 g)                                                            C-2 (Table 16)                                                                (0.2 g)                                                        41   Ba-20 (Table 9)                                                                         QD-4 (Table 1)                                                                           --       --       31 g                                   (9.0 g)   (1.0 g)                                                                       C-9 (Table 17)                                                                (0.5 g)                                                        42   Ba-25 (Table 9)                                                                         QD-4 (Table 1)                                                                           J-5 (Table 6)                                                                          W-1 (Table 19)                                                                         34 g                                   (8.0 g)   (1.0 g)    (6.0 g)  (0.5 g)                                    __________________________________________________________________________     ECA*: Eithyl Collosolve Acetate                                          

                                      TABLE 33                                    __________________________________________________________________________                Exposure        TMAH Solution                                          Pre-Baking                                                                           Amount                                                                             Post-Exposure                                                                            Concentration &                                                                         Resolution                              Example                                                                            Temp., Time                                                                          (mJ/cm.sup.2)                                                                      Baking Temp. & Time                                                                      Development Time                                                                        (μm)                                 __________________________________________________________________________    40   85° C.                                                                        10    85° C.                                                                           1.59%     0.35                                         3 min.      3 min.     30 sec.                                           41   100° C.                                                                       55   125° C.                                                                           1.59%     0.35                                         3 min.      2 min.     30 sec.                                           42   90° C.                                                                        70   120° C.                                                                           1.19%     0.35                                         5 min.      3 min.     50 sec.                                           __________________________________________________________________________

                                      TABLE 34                                    __________________________________________________________________________         Acid-Decomposable    Alkali-Soluble                                           Compound and                                                                            Acid Generator                                                                           Polymer and                                                                            Additive and                                                                           Amount of                         Example                                                                            Amount Thereof                                                                          and Amount Thereof                                                                       Amount Thereof                                                                         Amount Thereof                                                                         ECA* (Solvent)                    __________________________________________________________________________    43   B-12 (Table 14)                                                                         QD-1 (Table 1)                                                                           --       W-3 (Table 19)                                                                         32 g                                   (9.5 g)   (0.5 g)             (0.5 g)                                                   C-9 (Table 17)                                                                (0.5 g)                                                        44    B-8 (Table 13)                                                                         QD-4 (Table 1)                                                                           J-4 (Table 6)                                                                          W-2 (Table 19)                                                                         35 g                                   (5.5 g)   (0.5 g)    (4.5 g)  (0.8 g)                                                   C-2 (Table 16)                                                                (0.2 g)                                                        45   B-10 (Table 14)                                                                         C-10 (Table 17)                                                                          J-5 (Table 6)                                                                          --       35 g                                   (2.0 g)   (1.0 g)    (7.0 g)                                             46   B-11 (Table 14)                                                                         Q-17 (Table 4)                                                                           J-1 (Table 6)                                                                          --       34 g                                   (3.0 g)   (1.0 g)    (7.0 g)                                             __________________________________________________________________________     ECA*: Eithyl Collosolve Acetate                                          

                                      TABLE 35                                    __________________________________________________________________________                Exposure        TMAH Solution                                          Pre-Baking                                                                           Amount                                                                             Post-Exposure                                                                            Concentration &                                                                         Resolution                              Example                                                                            Temp., Time                                                                          (mJ/cm.sup.2)                                                                      Baking Temp. & Time                                                                      Development Time                                                                        (μm)                                 __________________________________________________________________________    43   80° C.                                                                        50    90° C.                                                                           1.59%     0.40                                         5 min.      2 min.     30 sec.                                           44   80° C.                                                                        15    90° C.                                                                           2.38%     0.40                                         5 min.      2 min.     40 sec.                                           45   100° C.                                                                       120  110° C.                                                                           1.59%     0.45                                         3 min.      5 min.     40 sec.                                           46   90° C.                                                                        60   120° C.                                                                           1.19%     0.45                                         5 min.      3 min.     50 sec.                                           __________________________________________________________________________

                                      TABLE 36                                    __________________________________________________________________________         Acid-Decomposable    Alkali-Soluble                                                                         Carboxylic                                      Compound and                                                                            Acid Generator                                                                           Polymer and                                                                            Acid and Amount of                         Example                                                                            Amount Thereof                                                                          and Amount Thereof                                                                       Amount Thereof                                                                         Amount Thereof                                                                         ECA.sup.1* (Solvent)              __________________________________________________________________________    55   Ba-35 (Table 9)                                                                         C-7 (Table 16)                                                                           J-1 (Table 6)                                                                          4-methyl 13   g                                 (3.0 g)   (0.2 g)    (1.0 g)  benzoic acid                                                                  (0.2 g)                                    56   Ba-35 (Table 9)                                                                         .sup.  QD-4 (Table 1)                                                                    J-4 (Table 6)                                                                          4-tert butyl                                                                           14   g                                           (0.44 g)   (2.0 g)  benzoic acid                                                                  (0.2 g)                                    57   Ba-35 (Table 9)                                                                         C-8 (Table 16)                                                                           J-1 (Table 6)                                                                          4-tert butyl                                                                           12.6 g                                 (3.0 g)   (0.1 g)    (1.0 g)  phenylacetic acid                                                             (0.1 g)                                    58   Ba-25 (Table 9)                                                                         QD-4.sup.2* (Table 1)                                                                    --       ascorbic acid                                                                          12.6 g                                 (4.0 g)   (0.21 g)            (0.1 g)                                    __________________________________________________________________________     ECA.sup.1* : Ethyl Cellosolve Acetate                                         QD4.sup.2* : Compound having esterification number of 3 per molecule     

                                      TABLE 37                                    __________________________________________________________________________                           TMAH Solution                                                                           Sensitivity                                       Pre-Baking                                                                           Post-Exposure                                                                            Concentration &                                                                         Exposure Amount                                                                        Resolution                          Example                                                                            Temp., Time                                                                          Baking Temp. & Time                                                                      Development Time                                                                        (mJ/cm.sup.2)                                                                          (μm)                             __________________________________________________________________________    55   80° C.                                                                         90° C.                                                                           2.38%     35       0.35                                     5 min. 3 min.     30 sec.                                                56   90° C.                                                                        120° C.                                                                           2.38%     52       0.30                                     5 min. 2 min.     30 sec.                                                57   100° C.                                                                       110° C.                                                                           2.38%     80       0.35                                     2 min. 2 min.     30 sec.                                                58   90° C.                                                                        105° C.                                                                           2.38%      70*     0.40                                     3 min. 2 min.     30 sec.                                                __________________________________________________________________________     Note: The sensitivity of Example 58, specified in the table, is the value     measured in the case color an iline stepper (NA: 0.50) was used as light      source.                                                                  

                                      TABLE 38                                    __________________________________________________________________________    Composition of the Resist                                                          Acid-Decomposable    Alkali-Soluble                                                                         Carboxylic                                      Compound and                                                                            Acid Generator                                                                           Polymer and                                                                            Acid and   Solvent                         Example                                                                            Amount Thereof                                                                          and Amount Thereof                                                                       Amount Thereof                                                                         Amount Thereof                                                                           and Amount                      __________________________________________________________________________                                                  Thereof                         59   Ba-30 (Table 9)                                                                         C-1 (Table 16)                                                                           --       2,2-dimethyl-3-                                                                          Ethyl                                (4.0 g)   (0.2 g)             hydroxypropanic acid                                                                     lactate                                                            (0.1 g)    (12.6 g)                        60   Bb-25 (Table 10)                                                                        C-1 (Table 16)                                                                           --       4-phenoxyacetic                                                                          Ethyl                                (4.0 g)   (0.44 g)            acid       lactate                                                            (0.1 g)    (12.6 g)                        61   B-13 (Table 15)                                                                         C-4 (Table 16)                                                                           --       3,4-dimethyl                                                                             ECA*                                 (4.0 g)   (0.1 g)             benzoic acid                                                                             (13.0 g)                                                           (0.1 g)                                    62   B-14 (Table 15)                                                                         C-1 (Table 16)                                                                           J-18 (Table 8)                                                                         α-phenyl                                                                           ECA*                                 (3.0 g)   (0.1 g)    (1.0 g)  propionic acid                                                                           (13.0 g)                                                           (0.1 g)                                    __________________________________________________________________________     ECA*: Ethyl Cellosolve Acetate                                           

                                      TABLE 39                                    __________________________________________________________________________                           TMAH Solution                                                                           Sensitivity                                       Pre-Baking                                                                           Post-Exposure                                                                            Concentration &                                                                         Exposure Amount                                                                        Resolution                          Example                                                                            Temp., Time                                                                          Baking Temp. & Time                                                                      Development Time                                                                        (mJ/cm.sup.2)                                                                          (μm)                             __________________________________________________________________________    59   80° C.                                                                         95° C.                                                                           2.38%     25       0.40                                     5 min. 3 min.     30 sec.                                                60   80° C.                                                                         95° C.                                                                           2.38%     20       0.40                                     5 min. 3 min.     30 sec.                                                61   90° C.                                                                        110° C.                                                                           2.38%     90       0.40                                     3 min. 2 min.     30 sec.                                                62   80° C.                                                                        100° C.                                                                           2.38%     25       0.40                                     3 min. 2 min.     30 sec.                                                __________________________________________________________________________

                                      TABLE 40                                    __________________________________________________________________________    Composition of the Resist                                                         Acid-Decomposable                                                                          Storong-Acid                                                                           Weak-Acid                                                                              Alkali-Soluble                                 Compound (Table 9)                                                                         Generator and                                                                          Generator and                                                                          Polymer and                                                                            Solvent and                       Resist                                                                            and Amount Thereof Used                                                                    Amount Thereof                                                                         Amount Thereof                                                                         Amount Thereof                                                                         Amount Thereof                    __________________________________________________________________________                                                Used                              RE-21                                                                             Ba-20        C-1 (Table 16)                                                                         D-2 (Table 18)                                                                         --       Ethyl lactate                         (5.0 g)      (0.025 g)                                                                              (0.56 g)          (16.7 g)                          RE-22                                                                             Ba-20        C-2 (Table 16)                                                                         D-3 (Table 18)                                                                         --       Ethyl lactate                         (5.0 g)      (0.05 g) (0.20 g)          (16.7 g)                          RE-23                                                                             Ba-20        C-3 (Table 16)                                                                         D-1 (Table 18)                                                                         --       ECA.sup.1*                            (5.0 g)      (0.29 g) (0.59 g)          (17.6 g)                          RE-24                                                                             Ba-25)       C-4 (Table 16)                                                                         D-4 (Table 18)                                                                         J-9 (Table 6)                                                                          CHN.sup.2*                            (4.0 g)      (0.05 g) (0.50 g) (1.5 g)  (16.7 g)                          RE-25                                                                             Ba-30        C-5 (Table 16)                                                                         D-5 (Table 18)                                                                         --       Ethyl lactate                         (10.0 g)      (0.3 g) (1.00 g)          (16.7 g)                          __________________________________________________________________________     ECA.sup.1* : Eithyl Collosolve Acetate                                        CHN.sup.2* : Cyclohexanone                                               

                                      TABLE 41                                    __________________________________________________________________________    Composition of the Resist                                                         Acid-Decomposable                                                                          Storong-Acid                                                                           Weak-Acid                                                                              Alkali-Soluble                                 Compound (Table 9)                                                                         Generator and                                                                          Generator and                                                                          Polymer and                                                                            Solvent and                       Resist                                                                            and Amount Thereof Used                                                                    Amount Thereof                                                                         Amount Thereof                                                                         Amount Thereof                                                                         Amount Thereof                    __________________________________________________________________________                                                Used                              RE-26                                                                             Ba-20        C-1 (Table 16)                                                                         D-1 (Table 18)                                                                         --       ECA*                                  (10.0 g)      (0.1 g) (0.30 g)          (31.2 g)                          RE-27                                                                             Ba-25        C-1 (Table 16)                                                                         D-6 (Table 18)                                                                         --       ECA*                                  (10.0 g)     (0.05 g) (0.50 g)          (31.6 g)                          RE-28                                                                             Ba-25        C-3 (Table 16)                                                                         D-1 (Table 18)                                                                         J-4 (Table 6)                                                                          Ethyl lactate                          (6.0 g)      (0.5 g) (1.00 g) (4.0 g)  (34.5 g)                          RE-29                                                                             Ba-30        C-6 (Table 16)                                                                         D-4 (Table 18)                                                                         --       ECA*                                  (10.0 g)     (0.25 g) (1.00 g)          (16.7 g)                          RE-30                                                                             Ba-20        C-3 (Table 16)                                                                         D-1 (Table 18)                                                                         J-13 (Table 7)                                                                         ECA*                                   (6.0 g)     (0.25 g) (0.30 g) (3.0 g)   (6.6 g)                          __________________________________________________________________________     ECA*: Eithyl Collosolve Acetate                                          

                                      TABLE 42                                    __________________________________________________________________________                                         TMAH Solution                                                                           Sensitivity                              Pre-Baking                                                                           Exposure                                                                              Post-Exposure                                                                             Concentration &                                                                         Exposure                                                                               Resolution            Example                                                                            Resist                                                                             Conditions                                                                           Condition                                                                             Baking Temp. & Time                                                                       Development Time                                                                        (mJ/cm.sup.2)                                                                          (μm)               __________________________________________________________________________    63   RE-21                                                                              95° C.                                                                        KrF                                                                              excimer                                                                            95° C.                                                                             1.19%     65       0.35                            90 sec.                                                                              laser                                                                            (NA0.45)                                                                           90 sec.     90 sec.                                  64   RE-22                                                                              80° C.                                                                        KrF                                                                              excimer                                                                            85° C.                                                                             1.19%     30       0.30                            90 sec.                                                                              laser                                                                            (NA0.45)                                                                           60 sec.     60 sec.                                  65   RE-23                                                                              90° C.                                                                        i-line                                                                           (NA0.50)                                                                           110° C.                                                                            2.38%     50       0.40                            180 sec.       120 sec.    50 sec.                                  66   RE-24                                                                              90° C.                                                                        KrF                                                                              excimer                                                                            100° C.                                                                            2.38%     75       0.35                            180 sec.                                                                             laser                                                                            (NA0.45)                                                                           120 sec.    50 sec.                                  67   RE-25                                                                              95° C.                                                                        KrF                                                                              excimer                                                                            95° C.                                                                             2.38%     60       0.40                            90 sec.                                                                              laser                                                                            (NA0.45)                                                                           90 sec.     50 sec.                                  __________________________________________________________________________

                                      TABLE 43                                    __________________________________________________________________________                                         TMAH Solution                                                                           Sensitivity                              Pre-Baking                                                                           Exposure                                                                              Post-Exposure                                                                             Concentration &                                                                         Exposure                                                                               Resolution            Example                                                                            Resist                                                                             Conditions                                                                           Condition                                                                             Baking Temp. & Time                                                                       Development Time                                                                        (mJ/cm.sup.2)                                                                          (μm)               __________________________________________________________________________    68   RE-26                                                                              95° C.                                                                        KrF                                                                              excimer                                                                             95° C.                                                                            2.38%     65       0.40                             90 sec.                                                                             laser                                                                            (NA0.45)                                                                            90 sec.    30 sec.                                  69   RE-27                                                                              95° C.                                                                        KrF                                                                              excimer                                                                             95° C.                                                                            1.19%     50       0.35                             90 sec.                                                                             laser                                                                            (NA0.45)                                                                            50 sec.    50 sec.                                  70   RE-28                                                                              90° C.                                                                        i-line                                                                           (NA0.50)                                                                           105° C.                                                                            2.38%     80       0.35                            180 sec.       120 sec.    30 sec.                                  71   RE-29                                                                              90° C.                                                                        KrF                                                                              excimer                                                                            105° C.                                                                            2.38%     70       0.35                            180 sec.                                                                             laser                                                                            (NA0.45)                                                                           120 sec.    30 sec.                                  __________________________________________________________________________

What is claimed is:
 1. A resist pattern forming methodcomprising:forming a resist film on a substrate, pattern-exposing theresist film, and developing the resist film thus pattern-exposed,wherein the resist comprises:(a) an acid-generating compound whichgenerates an acid when exposed to ultraviolet rays or ionizingradiation; and (b) a compound which has an acid decomposable substituentgroup and which is represented by the following formula (I) ##STR69##where R¹ is a monovalent organic group, and m and n satisfy thefollowing formula: n/(m+n)=0.17 to 0.60.
 2. The resist pattern formingmethod according to claim 1, wherein R¹ in the formula (I) istert-butyl.
 3. The resist pattern forming method according to claim 1,wherein said acid-generating compound is triphenylsulfoniumtrifluoromethanesulfonate.
 4. The resist pattern forming methodaccording to claim 1, wherein said acid-generating compound is an0-quinonediazide compound.
 5. The resist pattern forming methodaccording to claim 4, wherein said 0-quinonediazide compound is1-naphthoquinone-2-diazo-4-ester sulfonate.
 6. The resist patternforming method according to claim 1, wherein the acid generatingcompound is used in an amount of 0.1 to 30 wt %, based on the totalweight of the solid components of the resist.
 7. The resist patternforming method according to claim 1, wherein said resist furthercomprises an alkali soluble polymer.
 8. The resist pattern formingmethod according to claim 7, wherein said alkali soluble polymer is usedin an amount of 90 parts by weight or less, wherein the total amount ofsaid acid decomposable compound and said alkali soluble polymer is 100parts by weight.
 9. A resist pattern forming method comprising:forming aresist film on a substrate, forming a layer of an acidic water-solublepolymer on the resist film, pattern-exposing the resist film with thepolymer layer, and developing the pattern exposed resist film with thepolymer layer, wherein the resist comprises:(a) an acid generatingcompound which generates an acid when exposed to ultraviolet rays orionizing radiation; and (b) a compound which has an acid decomposablesubstituent group and which is represented by the following formula (I)##STR70## where R¹ is a monovalent organic group, m is 0, 1 or apositive number greater than 1, and n is a positive number.
 10. Theresist pattern forming method according to claim 9, wherein R¹ in theformula (I) is tert-butyl.
 11. The resist pattern forming methodaccording to claim 9, wherein the acid water-soluble polymer has acarboxy group or a sulfo group as a substituent group.
 12. The resistpattern forming method according to claim 9, wherein the acidicwater-soluble polymer is at least one polymer selected from the groupconsisting of polyacrylic acid, polymethacrylic acid,polystyrenesulfonic acid, polymalic acid, polyitaconic acid,ethylene-anhydrous maleic acid copolymer, ethylene-methacrylic acidcopolymer, ethylvinylether-anhydrous maleic acid copolymer andstyrene-anhydrous maleic acid copolymer.
 13. The resist pattern formingmethod according to claim 9, wherein said acid-generating compound istriphenylsulfonium trifluoromethanesulfonate.
 14. The resist patternforming method according to claim 9, wherein said acid-generatingcompound is an o-quinonediazide compound.
 15. The resist pattern formingmethod according to claim 14, wherein said o-quinonediazide compound is1-naphthoquinone-2-diazo-4-ester sulfonate.
 16. The resist patternforming method according to claim 9, wherein the acid generatingcompound is used in an amount of 0.1 to 30 wt %, based on the totalweight of the solid components of the resist.
 17. The resist patternforming method according to claim 9, wherein said resist furthercomprises an alkali soluble polymer.
 18. The resist pattern formingmethod according to claim 17, wherein said alkali soluble polymer isused in an amount of 90 parts by weight or less, where the total amountof said acid decomposable compound and said alkali soluble polymer is100 parts by weight.